Data Recovery Ireland

ECC (Error Correction Code) plays a crucial role in maintaining the integrity of data stored inside your solid state drive. ECC is a bit like a quality-control inspector inside your disk. When it detects soft bit errors, it automatically corrects them helping to keep the integrity of your data is kept intact.

However, sometimes, due to defects such as wear of the oxide layer, ECC failure will occur. Here your SSD controller has another trick up its sleeve. Many SSDs employ what are known as “superpages”. These are tracts of data spread across multiple dies. For example, you might have an SSD with 4 dies (NAND chips). If you have a data (a 200 page PDF document, for instance) stored on your SSD, the file probably won’t just be stored on one chip. Instead, it will be spread out among the 4 chips. The data is then XOR’ed. This is kind of analogous to the way data is stored in RAID volumes. The spreading of multiple I/O requests to multiple dies means much faster processing times. Now, even if ECC is unable to rectify the bit-errors, using superpage-level parity, data recovery is still possible.

For example, a client recently presented us with an Asenno 240GB SSD. There were numerous un-correctable bit-error showing.  Using the power superpages along with some powerful data recovery equipment, we were able to recover the complete NTFS volume for the client.

Drive Rescue (Dublin, Ireland) offer a complete data recovery service for Asenno 240GB, 480GB, 512GB, 960GB and 1TB (S-ATA and NVMe PCIe) SSDs. Typical problems we help with include:

• Your Asenno SSD is not showing up in Windows or macOS
• Your Asenno SSD appears to be corrupted
• Your Asenno SSD is appearing as “unallocated” in Windows Disk Management
• You’ve accidentally deleted files from your Asenno SSD
• You’ve got a BIOS-level warning that “SMART failure” is predicted on your Asenno disk.
• Your Asenno disk appears as “unformatted” in Windows Explorer or macOS Finder

DAS (or direct access storage) devices are ideal for tasks involving high data throughput such as photo or 4K video editing. Unlike an NAS, no network equipment such as routers or switches are required. The device can simply be attached to a host system using a USB or Thunderbolt connection.

To increase the I/O (input / output) rates of these devices, it is common for manufacturers to use a RAID 0 configuration. This simply means that two (usually S-ATA HDDs) disks are joined at the hip (using software) to form one (NTFS, HFS+, EXT3 etc.,) data volume. If large files need to be transferred to the volume, the data is written concurrently to the two disks (instead of just one) making the write operation faster.  For example,  typical write speeds would be around 320 MB/s. This is a relatively fast speed for spinning metal platters and is a perfect example of how storage devices can exploit data parallelism afforded by RAID.  

However, there is a downside to using RAID’ed disks like this. Namely if one disk fails, the whole volume topples over like a proverbial house of cards. And this is exactly what happened to a customer we were helping last week. Their 8TB G-RAID (12V 5Amp) device had two HGST 4TB S-ATA disks (HUS726040ALE614) in a RAID 0 configuration. One of the HGST disks developed firmware issues and bad sectors causing the volume to become unrecognised by Windows. When our customer connected his G-RAID drive to his Windows 10 system, it was no longer showing up. Instead, they got an ominous red light on power up.  

Reasons why your G-Technology G-RAID drive no longer shows up in Windows or Mac.

• One or more of the disks inside your G-RAID drive might have developed physical faults such as issues with the read-write heads. For example, heads can physically deform due to shock damage while some heads will just fail due to wear-and-tear. Problems with the read-write heads can make the MBR (master boot record), the firmware on the servo-tracks and the user-created data of each disk unreadable.
• One or more of the disks inside your drive might have developed firmware faults. Firmware is microcode used by hard disks to manage the drive. It is typically stored on the ROM chip of the PCB and on the servo tracks of the disk. Firmware code helps manage errors on the disk and is also involved in crucial functions such as logical block addressing.
• Another reason why your G-RAID rive is no longer being detected is that one or more of your disks inside your 4TB or 8TB G-RAID drive might have developed bad sectors. Sectors are the smallest area in a hard drive where data is stored. Some bad sectors are normal. In fact, most electro-mechanical hard disks leave the factory with some bad sectors already in place (this is recorded in the P-List). As the disks gets used, more bad sectors start to develop – these are recorded on the G-List. Then, after a while, a surfeit of bad sectors may culminate in your G-RAID drive failing to initialise.
• The PCB (printed circuit board) inside your G-Technology G-RAID drive might have failed. This can occur due to thermal stress, over-voltage (e.g. a power surge) or due to liquid damage.  

Data recovery from a G-RAID device

Thankfully most of the problems with G-RAID drives can be fixed. In this particular case, we resolved the issues with the firmware and bad sectors. The using byte-for-byte disk images, we performed a detailed analysis on them ascertaining key RAID parameters that were used such as disk order, block size, block order and disk offsets. All of these are parameters are needed for the RAID rebuild process. We eventually rebuilt the RAID. We now had a complete NTFS volume and were able to recover all the drive’s data (video footage and .tiff images) for our very pleased customer.

Is your G-RAID drive not mounting on your Mac? Is your G-RAID drive not showing in Windows? Is your G-RAID disk freezing? Is your iMac or MacBook reporting that your G-RAID disk is “not readable”. Is your G-RAID drive showing a red light? Drive Rescue offer a complete data recovery service for G-RAID devices such as G-RAID Thunderbolt 4TB, 8TB and 12TB. We have extensive experience in recovering and repairing the hard disks (usually HGST 3.5” S-ATA) used inside these drives.

So called “Ultra small form factor” PCs have never been so popular for their compactness, versatility and low power consumption. You can hold them easily with one hand and most are lighter than a dictionary. In fact, during the pandemic, some organisations were able to dispatch these book-size PCs to their home-working employees in the post. All the employee had to do was connect the system to a monitor cable (HDMI, DPI), mouse and keyboard and they were up and running in no time.   

While all this sounds great, but here at Drive Rescue we’ve noticed one thing. Some of the disks inside these ultra small form factor PCs, seem to experience higher-than-average failure rates. This is not surprising. While very convenient, most of these systems do not offer the same level of airflow as their more internally capacious brethren. Even with sophisticated heat sink designs, lower levels of internal airflow, mean that inside, the components (such as northbridge chip) and disks inside these systems can get hotter than a Tokyo metro train during rush hour during a heatwave.

And that’s not good news for HDDs or SSDs. Conventional hard disks (P-ATA, S-ATA) never liked the heat. They have too many metal components (such as platters, spindles, sliders and voice-coil motors) inside which expand when exposed to heat. SSDs (such as M.2 NVMe) on the other hand, actually run better when hot, but after a while this heat-induced performance boost begins to take a toll on the disk’s controller. Too much heat can cause the controller to execute failed bad block management operations, failed logical block addressing and eventually the thermal stress can culminate in complete failure of the controller IC itself.

How to recover data from a Lenovo small form factor PC?

Take last week for example, we were recovering data from a Lenovo IdeaCentre Q180. The disk inside a WD Blue 500GB S-ATA (WD5000LPVX) had a failed head-disk assembly (HDA). More specifically, the head-gimbal assembly at the end of the HDA had “lifted” from the fly zone. Damage in congruence with thermal stress. Anyway, we replaced the HDA in our clean-room, we then imaged the disk enabling a full data extraction from it’s NTFS partition table.

Drive Rescue (Dublin) offer a complete data recovery service for small form factor PCs such as Fujitsu Esprimo E420, G5011, G5010, Q520, Q910, Q958, Intel Nuc, Lenovo ThinkCenre M700, M900, M710s, M710q, ThinkStation P350, Dell Optiplex 780,790,3020,3050,7010, 7040,9020m and Asus PN50, PN60. We recover from most disk types used in these systems including M.2 NVMe (SSD) disks, m-SATA and S-ATA disks.   

For conventional hard disks (HDDs), the smallest unit of storage is called a sector. This traditionally has been 512 bytes with most hard disks of the last 10 years or so using 4096-byte sectors (Advanced Format). Each sector will hold the user-generated data, sync bytes but will also hold some ECC (Error Correction Code) to maintain the integrity of the data. The ECC acts as a sort of checksum to filter out corrupt data before it’s transmitted to the host’s RAM.

The problem with ECC

Modern ECC algorithms (such as Reed-Solomon and Bose-Chaudhuri-Hocquenghem) are great, they help prevent bit-rot and other corrupting processes. However, when you have a failing hard disk with bad sectors and try to read it on a standard PC, ECC will probably be the reason that the disk can’t be read. The host computer attempts to read the sectors once but ECC will report the sectors as unreadable. To the user, they will probably see a “not responding error” or similar on their GUI. ECC is a fusspot in this regard – any corruption at all and it won’t let the host PC read the data.

ECC and consumer-grade data recovery software

ECC is not only problematic for reading failing disks via an operating system, but it is also one of the main reasons why so many consumer-grade data recovery software applications can’t recover data. Like with operating systems, data recovery applications cannot always read from sectors whose ECC is reporting errors. In order to bypass this, these applications will read and re-read inaccessible sectors multiple times in the hope that ECC might allow a successful read. However, for a hard disk that is failing or damaged, these repeated attempts of reading are the equivalent of torture for your disk.

It’s not only ECC…

ATA controllers, as used in standard PCs, require that data transfers from disk to host use the host’s RAM. This can be problematic, especially when processing disks with bad sectors or read-media issues as BSOD events are likely. In addition to this, ATA controllers in standard PCs cannot perform disk re-set operations.  

How professional data recovery equipment circumvents ECC errors and the problems associated with standard ATA disk controllers…

• Data recovery technicians use dedicated hardware systems that enable disk-reads that bypass the BIOS and the operating system. They use systems which can ignore ECC errors.
• Moreover, technicians use equipment which can directly read the disk’s error register. This gives the technician (and equipment) much more specific information about the underlying problem. For example, this could be a UNC (un-correctable) data error or a TONF (track not found) error. When the equipment knows what the underlying fault is, it can choose a recovery algorithm to maximise the probability of a successful recovery.    
• Data recovery technicians will typically use systems with ATA disk controllers equipped with Ultra Direct Memory Access. This enables direct data transfers whilst bypassing the host’s RAM.
• ATA controllers used in standard computers cannot perform disk re-set operations if the disk becomes unresponsive. A disk re-set operation is much less stressful on a failing hard disk compared to a re-power operation.  

Only last week, we were dealing with a very frustrated end-user who was trying to extract data off his LaCie Rugged Thunderbolt USB 3.0 2TB external hard drive. Everything time he connected the disk via a Thunderbolt port to his MacOS system, it would freeze. He found this very frustrating. He had thousands of Adobe PhotoShop (PSD) and Adobe Premiere Pro (PRPROJ) which he needed to transfer to another working disk. Our diagnostics revealed that the disk inside (Seagate Barracuda 2TB ST2000LM015) had developed extensive bad sectors. Using our ECC-bypassing and UDMA-enabled data recovery systems, we were able to transfer his data to his second disk within 48 hours.

Drive Rescue (Dublin, Ireland) offers a complete data recovery service for LaCie Rugged disks. We regularly recover from models such as LaCie Rugged Mini, LaCie Rugged USB-C, LaCie Rugged 3TB LaCie Rugged 4TB, LaCie Rugged 5Tb which are not mounting or not recognised in Mac. Likewise, we recover from LaCie external disks which are showing up in Windows (10 or 11) or from LaCie disks which are making a clicking or buzzing noise.

Having your Apple MacOS stuck in a dreaded boot loop can be an exasperating experience. (For those of you lucky enough not to know what a boot loop is, it occurs when an operating system cannot successfully boot to the desktop screen. Instead, on system power-up, the OS goes through the familiar boot-up process but halts at a certain point. If you’re lucky, you’ll get an error message which might give a hint of what the problem might be). In MacOS, boot loops can occur out-of-the-blue due to OS corruption or they can typically occur after the user has attempted to install a fresh version or updated version of their operating system.

Recently, we had a client who experienced this very problem. They tried to upgrade their operating system from Catalina to Big Sur. However, their 256GB SSD did not have enough space. The installation of the OS update files never completed, but now on start-up of their system they would receive a message that “An error occurred preparing the software update”. As a result, they were unable to access their desktop and they had no recent backup.

Luckily, we had heard about this problem before. The earlier versions of the MacOS Big Sur (11.6.1, 11.6.2) installer files have a bug in them. Namely, the installer setup file does not check the size of the disk before the installation process begins proper. Therefore, if you don’t have the pre-requisite of 35GB of free space needed to store the temporary install files, this re-boot loop problem manifests itself. This bug also interferes with FileVault 2 encryption hence making the APFS volume invisible to Target Disk Mode (TDM). TDM will see “Macintosh HD” but not “Macintosh HD – Data” which is the folder you want! And if you’re thinking some bootable Linux tool could image the disk – because of the problem with FileVault 2, that avenue is also closed off.

Thankfully, there is a solution to this problem, albeit convoluted, which goes beyond the scope of this blog. But the long and short of it is this; we got all the data back for our delighted client. The lessons of this case are simple. Always have a complete backup before you start upgrading your MacOS system (or any OS for that matter). And secondly, always try to avoid deploying the first iterations of an operating system because, even with MacOS, these versions can be more bug prone.

Drive Rescue offer a data recovery service for Apple in Dublin, Ireland for devices such as MacBook Air, MacBook Pro and iMacs. We’ve been recovering data from Apple devices since 2007 with excellent success rates.

Why is SSD firmware super-important to running of your disk?

The host system does not directly interface with the NAND containing your data. Instead, it interfaces with the firmware directly. The firmware holds the File Translation Layer which maps physical blocks to logical blocks. The firmware also performs crucial tasks like data scrambling, bad block management, interleaving, wear levelling and TRIM.

Isn’t firmware the code that’s also used in personal printers, toasters and fitness monitors right?

Yes, but in storage devices such as HDDs and SSDs it tends to more multi-faceted and much more complex. For example, Travis Goodspeed giving his talk “Implementation and implications of a stealth hard-drive backdoor” at Sec-T (2014) revealed how it took him “10 man months” to reverse engineer a Seagate Barracuda hard disk. He and his team also had to “kill” 15 hard disks in the process. So yes, the firmware found in your HDD or SSD is in a different ballpark than the firmware found in your Fitbit.   

So, why bother updating the firmware on your SSD?

Well, if a potential problem is discovered it can often be remedied by a pre-emptive firmware update. Now you might be thinking that it’s the disk manufacturers themselves who discover these faults, right? Well, in most cases, it’s usually their customers such as gamers, PC enthusiasts and sys admins who discover them. Such problems could be related TRIM, ECC, bad block management or write amplification. When a problem is discovered, and assuming the disk model in question has a sufficiently large user base, it kind of expected that the manufacturer will release a firmware update to remedy the issue.

Could a firmware update for my SSD brick my drive?

Quite frankly, yes. This is why you should avoid the temptation of hastily applying recently released firmware updates from manufacturers. Because it’s not unknown for a vendor to release a firmware update which can provoke undesirable side-effects (such as dramatic slow-downs of the disk) or in worst case scenarios turning your SSD into a doorstop. This can happen if, for example, if the PMIC (power management IC) or file translation lay (FTL) gets corrupted. Of course, you’re also looking at potential data loss. This is why you should always perform complete disk backup before attempting any firmware update on your SSD.

So, I’ve backed up my data. Now, I can’t apply the firmware update using the manufacturer’s SSD utility (such as Samsung Magician, Crucial Storage Executive, Kingston SSD Manager etc.). What now?

Ok, truth be told. Updating your SSD’s firmware, even with the manufacturers dedicated utility software is rarely a click-and-go process. Some questions to ask before even starting include: are you using the latest version of the utility? Are you running the tool as an administrator? Have you performed a re-boot of your system after installing the SSD utility for the first time? Have you tried disabling your anti-virus or other end-point security software? Is your disk attached directly to your motherboard via a S-ATA or M.2 connection?

I’ve tried all of the above but still can’t apply the firmware update to my SSD. What do I do now?

If all of the above suggestions fail, you may need to create a bootable ISO tool provided by your manufacturer. Such a tool can avoid the layers of abstraction presented by an operating system such Windows. It can also make the firmware update process run more smoothly. So, after you’ve downloaded the ISO file, you need to make it bootable. You can do this using a tool such as the excellent Rufus USB creator.  Once your bootable USB SSD utility has been created, boot up your system with it. It should allow you to update your disk’s firmware without the operating system getting in the way.  

I think my SSD is failing, will a firmware update fix it?

Applying a firmware update to a failing SSD might actually exacerbate your problem. Writing new firmware to a disk often means that the existing firmware gets wiped. However, if your disk is failing and the new firmware module is unable to be written (to your SSD) – this leaves you in a sort of firmware no man’s land and potentially irreversible data loss. Professional data recovery companies such as Drive Rescue circumvent this problem by using a firmware “loader”. This basically means that the new firmware is loaded onto one of our host systems first and this is then used a “translator” to read the NAND whilst leaving the original firmware intact.

Drive Rescue, Dublin offer a complete data recovery service for faulty or inaccessible SSDs. Popular models we recover from include SK Hynix PC300, PC401 PC601, PC711, Micron 1100 M.2, Micron 1100 S-ATA, Micron 2200, Micron 2300, Samsung Mzvlb256hbhq-000l7, Mzvlb256hbhq-000l7, Mzvlb512hajq, Mzvlb512hajq, PM853T, PM871, PM883, PM991, Kingston A400, Kingston SSDnow SV300, SSDNow V300 and Toshiba Thnsnk256gvn8.

Having data lost due to hard disk failure can be gut-wrenching. But having your data encrypted or wiped by remote hackers can be equally so. You might have heard that QNAP NAS devices have been recently subjected to yet another ransomware attack. And you might remember that during the summer WD My Book Live were subject to remote hackers running data wiping software on them.

In the most recent QNAP case, the attackers used 7-Zip to move files on QNAP devices into malicious password-protected archives and encrypt QNAP NAS devices worldwide. Frenzied users across the globe reported how even though their devices were using updated versions of firmware and QTS (NAS Operating System), they still got hacked.

The problem with NAS devices

One of the problems with NAS devices is that ease-of-use is prioritised over security. This problem has been compounded by manufacturers prioritising features over security. Some NAS devices now come bundled with more apps than a teenyboppers smartphone. While more apps might sound great, it exponentially increases your NAS device’s attack surface.  

How do I prevent my own NAS or my client’s devices from getting hacked?

First of all, your NAS shouldn’t be connected to the internet at all. However, some users will still want to connect their NAS devices to the internet for remote access, so we’ve included some tips anyway.

Change default usernames and passwords. Do not, for example, use “admin” as the default username. This is exactly why so many QNAP users get caught out by the QSnatch botnet, which first spotted in 2019. It was programmed to launch a brute-force attack against devices using the default “admin” as a username. As for choosing a password, make sure it’s complex and uncommon.

For example, “liverp@@lfc” is not considered a secure password. While it’s complex, it too common to be secure. Would a hacker’s brute-force password database have this? – probably. Use the online Kaspersky Password checker to test the robustness and strength of your password.   

Avoid the temptation of using remote NAS access services such as MyQnapCloud, Synology’s Quick Connect service or LaCies’ MyNAS service. While these services are very convenient, they poke a hole in your router, which makes your device, internal network and data more exposed to external attacks.

While many NAS boxes now come equipped with onboard VPN services, such as OpenVPN, you might also want to give these services a wide berth. Just one firmware zero-day attack on your NAS makes it more porous than Swiss cheese.

Instead, if you really need to access your NAS remotely, access it using a VPN connection provided by your firewall device (SonicWall, Fortinet etc). If you don’t have a firewall, you can use VPN services such as Wireguard coupled with Tailscale. Or, you could try accessing your NAS remotely using a service such as ZeroTier.

Disable UPnP port forwarding on your NAS and router to prevent brute-forcing attacks from external attackers.

Make sure FTP access to your NAS is disabled. FTP is an old and insecure file transfer protocol that should never be enabled on your NAS. In fact, if remote access is not required, disable all internet services on your NAS except for DNS and NTP.

Disable multiple login attempts to your NAS (called AutoBlock in Synology devices)

I have permissions set on my NAS so that only the “administrator” can write to it?

A lot of malware in circulation these days uses “privilege escalation“ to bypass read/write and erase permissions. So unfortunately this does not afford you a great deal of protection against ransomware or “wiper” malware.

I have setup my backup application to run snapshots to my NAS, will that protect me?

Not always. Snapshots can get wiped by disk-wiping malware.

So, is it only Synology and QNAP?

Not true, in March 2020 a new variant of the Mirai botnet was scanning TCP ports looking for Zyxel NAS devices. The password brute-forcing attacks would then force vulnerable Zyxel NAS devices offline by using a DDoS attack. In February 2019, D-Link NAS devices were subject to Cr1ptT0r Ransomware. In fact, the situation got so bad, D-Link even began issuing firmware updates for end-of-life NAS boxes.   

If I follow all these guidelines, will my NAS be secure now?

No! A zero-day exploit could be discovered tomorrow, which makes your NAS vulnerable. Always follow the 3-2-1 backup methodology. 3 copies of data. 2 on different mediums and 1 backup off-site.

Never forget that a NAS device is not a backup in itself if you don’t have the data stored elsewhere. Some users buy a second NAS for the purposes of backup. This is an option which is well worth considering.

Can data be recovered from a NAS which has been subjected to a ransomware or malware attack?

Sometimes cyber criminals will deploy their malicious encryption software with an inadvertent bug in it. This allows some software vendors (such as Emsisoft) to release a “fix” or “decryption” tool which can mean successful restoration of data.

When it comes to data-wiping malware, sometimes it will only delete file system (EXT3, EXT4, NTFS, XFS etc.) metadata. This then makes a raw data recovery (recovery without original file structure) possible.  

Drive Rescue, Dublin Ireland offer a complete NAS data recovery service for Synology (DS120, DS414, DS416, DS718) , QNAP (TS-219, TS-251,TS-451,TS-453), WD My Book, WD My Cloud, WD My Cloud EX2, WD My Cloud EX2 Ultra, Buffalo (LInkstation + Terrastation) and LaCie (2Big, 4Big, 6Big and 8Big)

Here are some of the the top reasons for SSD (S-ATA, PCIe NVMe and m-SATA) failure which we’ve come across in the Drive Rescue lab last year:

1. _{File Translation Layer corruption}
2. _{Bad Blocks}
3. _{Gate-oxide Failure}
4. _{Failure of solder-joints on printed circuit board}
5. _{Exhausted NAND}
6. _{Failure of Power Management IC}
7. _{Read Disturb Failures}
8. _{DRAM-chip Failure}
9. _{Wear-out of System Area containing firmware}
10. _{Complete NAND Chip Failure}

The above list covers failure modes across all brands and interface types of solid state disk including Samsung, Micron, SK Hynix, WD, Toshiba, HP, Kingston and Apple models. You can find out more our SSD data recovery service here

One of the great drawbacks of the electro-mechanical disks is their propensity to develop bad sectors. And unfortunately, SSDs don’t escape this problem.

Bad sectors are a problem for storage devices simply because they can result in inaccessible or lost data. Moreover, bad sectors often have a happy knack of developing in the same areas of your disk where your most important data is stored.

Typical Symptoms of Bad Sectors on an SSD include:

• Your S-ATA or PCIe SSD (such as Samsung, Micron, SK Hynix etc) is causing your computer to intermittently freeze.
• In Window’s Event Viewer, you see evidence of “bad blocks”  being reported.
• Your S-ATA, PCIe (NVMe) or USB (3.1 / USB-C) SSD is not being recognised by your computer
• You can see your SSD’s folders and files in Finder (MacOS) or Explorer (Windows) but cannot copy them to another medium.
• You’re receive an “access is denied” error message when you try to access your Micron SSD in Windows.
• In MacOS, you see error messages like “First Aid found corruption” after running in-built disk repair utilities. Or, you see messages like “The disk you inserted was not readable by this computer”
• You’ve tried running a data recovery program like EaseUs or Recuva but it keeps on freezing.
• Checkdisk (Chkdsk) freezes at a particular point.

So, why do bad sectors or bad blocks develop on SSDs?

Well, there are a number of reasons. First of all, like with HDDs, SSDs actually leave the factory with some factory-marked bad blocks. This is because the manufacturing process for NAND is not perfect. Imperfections in the NAND wafer, from which NAND dies are cut, are almost inevitable.

As the SSD gets used, grown bad blocks (sometimes known as runtime bad blocks) start to develop. These can occur for a number of reasons including:

Wear and Tear – The insulation layer of the tunnel oxide in NAND cells begins to degrade due to the Fowler-Nordheim tunnelling process which occurs during P/E (Program/Erase) cycles. Altough the wear levelling (WL) algorithms are designed to evenly distribute block usage across the volume, WL is not a perfect process. And don’t forget that some types of NAND have lower endurance than others. On one end of the spectrum, you have high-endurance SLC NAND (which is actually rarely used even in industrial-class SSDs) while at the other end you have QLC NAND which is considered low endurance NAND. Or, to put it into perspective, a 1TB TLC SSD would typically have an endurance rating of 1 DWPD (Data Writes Per Day) while a 1TB QLC SSD would typically have an endurance rating of just .1 DWPD.  

• Trapped Charge – Sometimes after prolonged usage, electronic charges can get trapped in the nitride layer between the NAND cells. This makes the voltage threshold for program/read or erase operations too high resulting in unreadable or unerasable sectors. The trapped charge problem can also be caused by improper shutdowns of the host system or by power supply issues with the SSD.  
• Prolonged Storage – If flash-based storage devices such as SSDs have been left powered-off for a while, they can lose charge. This retention loss can result in blocks becoming unreadable and being marked bad by the disk’s Status Register. These bad blocks are also added to the Bad Block Table. Some SSD manufacturers include “refresh” algorithms in their controllers which are designed to recharge cells when the device is connected.
• Disturb Failure – NAND cells can get “disturbed” when a bit is unintentionally programmed from a “1” to “0” or vice versa. This occurs when the voltage for cells-to-programmed creates an electric field which interferes with neighbouring cells.  
• Bad blocks or bad sectors can become very problematic when they start to develop in the System Area of an SSD. This can result in unreadable firmware or unreadable boot initialisation code. The latter scenario can result in your SSD failing to be recognised by your computer.Bad blocks occurring in the user addressable area of the disk can be managed. Most SSDs have a Bad Block Management (BBM) feature which marks blocks as bad (unreadable). BBM then uses “good” cells from the reserved section of the disk to substitute for the bad ones.

Fixing Bad Sectors on SSDs

Over the years commercial products have been patented and developed to cure bad sectors using methods such as hysteresis. But most of these solutions never really resolved the bad sector problem. Just as with HDDs, there is no real way to fix bad sectors on an SSD. However, an experienced data recovery technician can work around bad sectors and try and recover as much as your data as possible using specialised equipment.

Examples of specialised data recovery equipment include:

Slow Sector Reading

Equipment which slow-reads of sectors. The read timeout parameters on a standard operating system are configured for healthy disks. Data recovery equipment allows the technician to read the disk using modified read timeout settings. This means that sectors which a standard operating system such as (MacOS, Windows or a Linux-based OS) would report as “unreadable” are actually readable by the equipment.

Smaller Sector Sizes

Equipment which uses variable sector sizes. For example, an Apple MacOS system will typically read disks in increments of 4096 bytes. Professional-level data recovery equipment allows the technician to read data in increments as low as 16 bytes. This sort of granularity, along with delayed-reads, allows for successful data recovery from bad sector areas.

Firmware Emulation

Data recovery companies can use equipment which can change the voltage supply to an SSD. This means that an S-ATA or PCIe (NVMe) SSD which is unreadable to a standard computer can be successfully read.If the System Area of your SSD has become damaged due to bad sectors, a firmware emulator can be used by a data recovery company to substitute for the original. This can result in previously inaccessible data being made accessible again.

Data Recovery from a Micron 2300 SSD

Here at Drive Rescue we recently came across a prime example of how bad sectors can affect a disk. The Micron 2300 512GB M.2 disk was taken from a Dell laptop. In the BIOS, the system reported SMART predictive failure. The disk was being recognised by the BIOS but not by Windows Explorer. The disk used an M.2 form factor and used 96-layer TLC NAND coupled with an in-house Micron controller. Initial diagnostics reveal that several firmware modules could not be read. Therefore, we used a firmware emulator to substitute for the damaged controller. However, the disk was still reporting extensive bad blocks. We set our data recovery equipment to use a read-timeout of over 20,000 milliseconds. We also set the sector retry rate to 3. Moreover, we used a read block size of just 64 sectors. These parameters gave substantially healthier disk-reads. After almost 24 hours on our recovery bench, the results were very pleasing. The most important files for our project manager client were .XLSX. PDF and .MPP (MS Project). These were all successfully recovered. They only files which were not recovered were some .MOV files which the client could download again anyway. Case closed and our project manager could back to managing projects instead of the painful and time-consuming task of reconstructing files.

Drive Rescue, Dublin, Ireland offer a complete SSD data recovery service for failed Micron SSDs including models such as Micron C300, Micron C400, Micron 1100 256GB, Micron 1100 512GB, Micron 2210, Micron 2200s, Micron 2200v, Micron 2300 NVMe,  Micron 5100 Pro M.2, Micron 5200, Micron 5300, Micron M550, Micron mtfdhba512qfd, Micron mtfddav256tbn and Micron mtfddak512tbn. We recover from Micron SSDs that are not being detected or not recognised by your computer. We also recover from Bitlockered Micron SSDs. Excellent success rates and fast service.