Originally Posted by john_pb
Just some further feedback on this, in case someone comes across the same problem:
Once the Kindle booted properly, I registered it and checked that the firmware it was running was 5.0.0 - as expected with the "forensic" drive image.
I then uploaded the most recent Amazon firmware (5.0.4), making sure it was transferred to the device properly before disconnecting it from the PC.
Running the update went fine until reboot. This time there was no "Your Kindle needs repair" message, but it got stuck on "Please wait for your Kindle to reboot".
After about 2 hours of leaving it sit, I rebooted into diags using Mfg Tool, connected via SSH and once again ran
"dd if=/dev/zero of=/dev/mmcblk0p3 bs=4"
The Kindle then managed to boot and came back as a new, unregistered device. The firmware version is back to 5.0.0.
Can anyone shed any light on why the update fails like this? Is it possible to go from 5.0.0 to 5.0.4?
I will refrain from updating it for now. Needless to say, I'm not all that keen to update the second KT, which is running 5.0.1, either.
5.0.3 and earlier just patched existing files, which could cause problems on systems with modified files.
Amazon changed their upgrade method after I explained to their high-level techs that this was causing kindle bricking, and the return cost from some countries is much too high, so I have been helping debrick them. The techs I talked to agreed with my suggestions, but they could only make recommendations to the people who make these decisions. After I requested that amazon NOT continue their potentially dangerous upgrade method, they released 5.0.4 using a safer method, so that adds a lot to the respectability of the technical decision makers at amazon (at least in my book).
5.0.4 contains complete copies of files, and instead of patching them, it replaces them. Most of the files it writes during the update are identical to the original files for earlier versions, so it replaces modified files with originals in many cases, instead of patching them in ways that could brick a kindle. 5.0.4 also replaces the linux kernel used to boot the main partition.
So, it is MUCH safer to update to 5.0.4 than earlier versions.
A side effect is that a few hacks such as "screen rotation" are disabled when one of their modified files got replaced. This can be fixed by restoring their modified file, or reinstalling that hack.