Cards & flash · bench log · ADR-2025-3189
Two Refusals, and Not the Same Refusal.
He had stored the footage on a SanDisk SD card. And two machines had refused access to it; between them, they said more than either of them knew. In the camera, the card cannot be accessed
. The computer was even blunter: his Macbook is failing to recognise it at all
. Those are two very different statements. The first device located a card but could make nothing of what was written on it. The second device saw no card to locate. Side by side, these two statements point to the problem being in the card and not in either machine. They also provide an estimate of just how low the failure lies, which is a good deal more than most enquiries arrive with.
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What failed, and why.
There are two components of a memory card. The memory itself contains what was recorded on it and will continue to contain that data long after the rest of the surrounding equipment stops functioning. The second component is a small microcontroller whose sole purpose is to act as intermediary between the memory and any external devices such as cameras or computers. Once you understand this, his two devices cease to differ. His camera was able to detect that he had placed a card into it, received some sort of response from the card, and was unable to interpret the organisation of that response. His MacBook detected no response whatsoever from the card. This pattern indicates that the issue lies beyond the file system (the way data is organised) and lies instead with the microcontroller responsible for communicating with the memory. Therefore, a second reader or another lead or another computer would each produce the same result. The video itself is unaffected. Memory cards and sticks are priced at £250 + VAT on our published list, and receiving a first look is cost-free.
What the bench did with it.
The order of the job →| Equipment used | Its work on this job | The reason for it |
|---|---|---|
| PC-3000 SSD | Inquiry initiated at the microcontroller level first, prior to making any determination regarding the memory. | Operates at the controller level; therefore, neither motor nor heads are involved. |
| PC-3000 Flash | Identify the memory type from the chip library; read raw memory contents. | Directly reads the flash off the chips, going around the controller, with a maker-ID library kept updated here |
| UFS Explorer Professional Recovery | Correctly sequence data read from memory; restore original folder structure; display video content. | When other applications will not open it, this application will open APFS, ReFS, XFS, ZFS and Btrfs. |
What the bench did with it.
Ask the front end before touching the memory
No investigation originated at a desktop card reader. The memory card was instead connected to a bench-based test instrument. This bench-test instrument monitors both power usage (drawn by the memory card) and responses generated by the memory card. Additionally, if a microcontroller within a memory card has merely slowed down, it can be distinguished from one that is no longer responding. The power drawn was about what it should have drawn. However, regardless of the command or the speed used, it would not generate any responses, which is precisely the experience his MacBook had already had.
Past the front end, on to the memory
When a microcontroller ceases to function it cannot be persuaded back into operation and there is no logical basis for attempting to do so. The memory was identified via a chip-library search. Then, the raw memory contents were read directly, in the order that particular card had been keeping them (which is not an order any standard file system would recognise). A microcontroller that has failed carries no data with it. Data recorded remains recorded. Our task becomes simply determining how to read that data back correctly.
The order has to be rebuilt before files exist
Raw memory reads deliberately arrive in non-sequential fashion (correction codes over the top, a mask applied and pages allocated wherever there was space upon writing); each of those processes was reversed in succession until the data appeared in the organisational format the controller had once presented. Only after those corrections were completed did a standard file system appear upon that previously unorganised mass of data, with the folders where the camera had put them and the video inside them.
What went home.
Clips were played through before anything was described as recovered. Clips were transferred to new media for transport back to his location. He performed the single most beneficial action possible without realising it: he attempted to use the card twice in two different devices and then stopped, rather than trying every other reader and adapter in his house. The published price for a card is £250 + VAT, and he saw it before anyone started.
Begin here if yours is doing the same thing.
More work off the flash and SSD bench.
Yours doing something similar? Power it down first.
Published prices are fixed. Memory cards and USB sticks are £250 + VAT. Any stand-alone drive is £300 + VAT. Drive configurations containing multiple disks (RAID, NAS or server) start at £500 + VAT. First assessments are always complimentary. Thereafter, data recovery charges are also fixed in advance and in writing, so you'll always know how much you owe before paying any money. Shut it down, get a quote first (by phone or with the form), then send it in or drop it off at our Guildford intake laboratory, Monday to Friday, 9am to 5:30pm (no appointment needed). On most jobs you only pay if we recover your data.