Quote:
Originally Posted by nicolasmart
Well, if the "update_version.txt" says "FB03", then why can't I downgrade to something like 5.8.9.2, which also is a "FB03" package?
<snip snip >
, and isn't it possible to change the Target OTA revision and the Magic 1, Magic 2 and Minor numbers without resigning the package. Aren't those just some sort of meta data applied to the file, outside of the signature envelope?
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It does make sense that you should be able to change the target OTA of an FB03 package.
The problem is that FB03 packages don't come by themselves. Look at the file "update_kindle_all_new_paperwhite_5.8.9.2.bin" in a hex editor, and you see that it starts with 'SP01". This is the "
signing envelope" .
The entire FB03 package ( including the OTA target and magic numbers ) are signed, and that result is stored inside this signing envelope. That is why you cannot change the target ota of the FB03 package in a real update file.
The FB02 packages do not come packed inside signing envelopes, that is the reason we were able to use them to downgrade.