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It would have cost the agencies a lot more though (contracting fees), I highly doubt they'd have the technical capabilities to handle this. But it just goes to show that they didn't really reach out and were simply using it as a means to push their backdoor agenda. :(
What worse is that they (or at least Comey) explicitly said that NAND mirroring does not work. When he was testifying before Congress, we was asked by several Congress people about NAND mirroring and (if I remember correctly) said that the technical experts had looked into it. This is either gross incompetence or outright perjury.
Well for the FBI NAND mirroring might not be a solution.

In the article the author mentions that this technique can effectively damage the flash memory because you can get effectively into a state where you are causing wear due to writes.

In theory you can scale this up and copy the contents of memory into an FPGA which emulates NAND (both logically and physically) or just hold multiple copies on different chips but even the initial process is not without risk.

While it's easy to say that the FBI lied or was incompetent because they had a motive to say set a precedent, but given the FBI's own rules for what is a forensically accepted method of extracting data NAND mirroring can easily be considered as something that "doesn't work".

Perhaps the FBI had a valid reason for not doing NAND mirror [0]. However, I maintain that it is incompetent for the FBI director to testify before congress on the case and not be prepared with a basic answer to why the most obvious technical answer would not work. Similarly, with him saying in a press conference that it would not work.

Of course, the FBI director does not need to know this level of detail about every case, but given how much he appears to have known, he should not have been speaking about the case beyond directing people to ask the person in charge of the case.

[0] Although, I would argue, in cases where no alternative exists, if the FBI policies prevent NAND mirroring, they should be revisited. Even if it has the potential to be destructive, they would only be destroying otherwise unusable information.

[0] Although, I would argue, in cases where no alternative exists, if the FBI policies prevent NAND mirroring, they should be revisited. Even if it has the potential to be destructive, they would only be destroying otherwise unusable information.

Eh? no, destructive methods are a big no-no, this isn't a dichotomy.

The information ins't unusable, they can try force apple to unlock the phone, or wait until some one else comes that can do it without using a destructive method.

You can't destroy evidence because you can't do anything with it at the given time.

> In theory you can scale this up and copy the contents of memory into an FPGA ...

In practice it would have to be in external memory (DDR, flash, etc.) that the FPGA would use to back transactions because FPGAs don't have 32GB of memory capacity. Problems then become meeting bus timings that may very well be tuned for the PCB layout.

Yea they definitely just wanted the GovtOS from Apple. Basically would allow them to hack somebody's phone without them knowing. Whereas requiring them to disassemble the phone it would be more prone to error and take more time to do.
There are quite more parts to that, as well as the scope, logic analyzers and quite a few other components.

It doesn't end up to 1M$ but it's also not 50$.

It's stated in the end of the paper. Less than $100
With access to a research facility quality electronics lab, and they still haven't managed to create a functional backup on a new NAND chip.

"Unfortunately, the 1:1 backup copy did not work in the iPhone 5c. Even the boot Apple logo did not appear on the power up. There were some references to hidden partitions used in iPhone NAND storage which makes cloning a challenging task."

... keep reading
I kept reading, from what I understood they restored the copy on the original chip, not made a clone. They could use the backup process to restore a specific partition but then you have a problem of wear due to writes, they've said that a 6 pin passcode is unlikely to be able to be brute forced on a single NAND chip without inducing possible damage due to wear.

Edit: You are correct, I've misread it.