Error 6 while rewriting firmware

Dear users,

I’m tasked with saving an iPhone SE that’s currently bricked. During boot it will sit on the Apple logo screen and subsequently enter recovery mode on its own.

The simple answer would be to flash iOS 12 (it’s currently also running this but trying 11.4.1 yields the same results) back onto the device but during the flashing process iTunes will throw error 6. This happens right as the phone reboots, enters recovery mode, and subsequently shows the first progress bar. The progress bar will not fill even a tiny bit. The same result has been replicated on 3 machines so far.

I’ve also tried a third party flash tool (3u Tools) but it gives me the same problem. It won’t get past the “Updating S3E Firmware” stage.

In the iTunes log files I’m finding “Failed to update NAND firmware”, which leads me to believe the flash chip might be bad. After reflowing (I don’t have the tools at hand for a reball sadly) the chip I’m still getting the same issue.

Am I missing something or is it safe to assume the phone is dead?