Originally Posted by phonic
A couple things.
First, there was an issue with custom recovery starting in 4.1.2. Versions of both CWM and TWRP, up until that point, would NOT work at all with the 4.1.2 bootloader. So many people had to revert to the 4.1.1 bootloader. However, since then, CWM and TWRP released newer versions that were compatible. Those compatible versions should still work with 4.2, but if you try an older version, it will probably have the same issue as 4.1.2.
Second, you will NOT be able to use the OTA update, through the system updater, unless your tablet is almost completely stock. While certain things like root or busybox are irrelevant, having a custom recovery, custom kernel, frozen/removed/modified system apks, modified build.prop, etc. will cause the auto updater to fail. You can however use that OTA update zip file in a custom recovery (manually), but again, all the other items need to be stock. The OTA update is a bunch of patches. Unlike the full image (which you can download now), which is significantly larger, the OTA update doesn't actually have all the new files, it has the information necessary to patch your current files to bring them up to the current version. In order for that patch to work, it needs to verify that they are the correct (4.1.2) version. This is a safety precaution, since patching a modified file would cause significant problems. As such, it verifies the SHA1 checksum of all the files it looks at, and if a single one is either missing or modified, it aborts.
So, assuming that you are only running a custom recovery (and maybe root and busybox), the OTA update should work manually. You can always give it a shot - if it aborts, it will tell you why. You can either find it in /cache if your system downloaded it already, or manually download it to sdcard. Then flash it like any other zip. If it works, great. If it aborts, you can either troubleshoot why (ie: replace the file it doesn't like) or download the full image and flash manually. For people with a lot of customization, the latter option is usually the quickest.
First; THANK YOU!
when it goes thru the OTA update by itself and trying to install 4.2 update, it fails: assert failed apply_patch_check ("EMMC:/dev/block/platform/sdhci-tegra.3/by-name/LNX:5013504:c48Fe86c73fb.....etc (did not write it down entire message). but says Status 7 at the end.
I never seen this error message before. I understand if it complains about System/app folder, which did not, but complain about EMMC:/dev/block/platform/sdhci-tegra.3/by-name/LNX:5013504:c48Fe86c73fb..... no clue whatsoever..
EDIT: I went to cache folder, and saw last.log.dat file, I opened with text editor...it shows where it failed during OTA update, hope someone can ping point what the issue I am having.
tarting recovery on Wed Nov 14 16:49:19 2012
can't open /dev/tty0: No such file or directory
framebuffer: fd 3 (800 x 1280)
ClockworkMod Recovery v18.104.22.168
recovery filesystem table
0 /tmp ramdisk (null) (null) 0
1 /sdcard datamedia /dev/null (null) 0
2 /system ext4 /dev/block/platform/sdhci-tegra.3/by-name/APP (null) 0
3 /cache ext4 /dev/block/platform/sdhci-tegra.3/by-name/CAC (null) 0
4 /data ext4 /dev/block/platform/sdhci-tegra.3/by-name/UDA (null) 0
5 /recovery emmc /dev/block/platform/sdhci-tegra.3/by-name/SOS (null) 0
6 /boot emmc /dev/block/platform/sdhci-tegra.3/by-name/LNX (null) 0
W:Unable to get recovery.fstab info for /datadata during fstab generation!
W:Unable to get recovery.fstab info for /emmc during fstab generation!
W:Unable to get recovery.fstab info for /sd-ext during fstab generation!
I:Completed outputting fstab.
I:Got arguments from /cache/recovery/command
Command: "/sbin/recovery" "--update_package=/cache/094f6629314a.signed-nakasi-JOP40C-from-JZO54K.094f6629.zip"
ro.build.display.id=cm_grouper-userdebug 4.0.4 IMM76L eng.koush.20120721.115347 test-keys
ro.build.date=Sat Jul 21 11:55:15 PDT 2012
ro.build.description=cm_grouper-userdebug 4.0.4 IMM76L eng.koush.20120721.115347 test-keys
Finding update package...
I:Update location: /cache/094f6629314a.signed-nakasi-JOP40C-from-JZO54K.094f6629.zip
Opening update package...
I:1 key(s) loaded from /res/keys
Verifying update package...
I:comment is 1604 bytes; signature 1586 bytes from end
E:failed to verify whole-file signature
I:verify_file returned 1
E:signature verification failed
Verifying current system...
contents of partition "/dev/block/platform/sdhci-tegra.3/by-name/LNX" didn't match EMMC:/dev/block/platform/sdhci-tegra.3/by-name/LNX:5013504:c48f8e86c73fb2c2ba1794f5ec98e27c9e206e d5:5060608:319331fae14fec8a88063751475fce26bae328e 0
file "EMMC:/dev/block/platform/sdhci-tegra.3/by-name/LNX:5013504:c48f8e86c73fb2c2ba1794f5ec98e27c9e206e d5:5060608:319331fae14fec8a88063751475fce26bae328e 0" doesn't have any of expected sha1 sums; checking cache
failed to stat "/cache/saved.file": No such file or directory
failed to load cache file
script aborted: assert failed: apply_patch_check("EMMC:/dev/block/platform/sdhci-tegra.3/by-name/LNX:5013504:c48f8e86c73fb2c2ba1794f5ec98e27c9e206e d5:5060608:319331fae14fec8a88063751475fce26bae328e 0")
assert failed: apply_patch_check("EMMC:/dev/block/platform/sdhci-tegra.3/by-name/LNX:5013504:c48f8e86c73fb2c2ba1794f5ec98e27c9e206e d5:5060608:319331fae14fec8a88063751475fce26bae328e 0")
E:Error in /cache/094f6629314a.signed-nakasi-JOP40C-from-JZO54K.094f6629.zip