Originally Posted by knc1
As a side note (in speculation) -
Avoiding the GPLv3 may be why Amazon is sticking with such old software versions.
I wouldn't call it speculation, I'm almost sure that's the case.
I doubt that they changed GPL binaries between 5.2.0 and 5.3.0. Even if binaries are not equal, it could be caused by different compiler flags - source code could be the same.
Unfortunately, only GPLv3 infringement would give us real power to demand jailbreaking guide. All that GPLv2 can give us are sources, without any ability to put them on the device.