Originally Posted by geekmaster
It has worked for many people to install 5.0.0 and update from there, but the 5.0.0 kernel is probably 64-bytes too short (the flash header firmware length field needs the length of the flash header added to it).
The kernels were fine and the updates were successful as such. Only the KT would not boot into the home screen.
I found the real reason after booting into diag and looking up the archived logs in /var/local/log. I found segmentation faults and crashes of fc-cache because it indexed fonts on /mnt/us/fonts (where I put the custom fonts for 5.0.x)! Since 5.1.0 there is a /etc/fonts/conf.d/70-lab126-altfonts.conf that points to /mnt/us/fonts!
But I already know from my work with HackedUpReader that the stock libfreetype shipped with the KT is rather limited and crashes with several fonts. Most notably the regular DejaVuSans font.
Who would have thunk that the issue was lying in my user partition?
Now that we know how to crash the Kindle Touch with a simple font, who's writing the first jailbreak by putting a file into /mnt/us/fonts?