[Asus  Eee Pad Transformer Prime] Trekest:
The main thread of the update got messy and my guide was buried there so I'm opening a separate thread dedicated for help with the JB update (my first real contribution to XDA!).

Recommendations! prior to updating:

Delete and re-create the Voodoo root backup, just in case.

Unfreeze all frozen apps.

I'm still gathering all the info from the previous threads.

For those who rooted but are still locked, and having issues with updating, here's something that might help (continuing from: http://xdaforums.com/showpost.php?p=32091002&postcount=111):

This seems to help for those who unlocked as well.

There were 3 files missing from /system/xbin that were required for the update to work.

It was confirmed by several users that the same files are applicable for all regional software variants.

Missing files:

http://www.mediafire.com/?cqccrt70xyrxjwz

The US update file (thanks Wipeout and Bait-Fish):

http://www.mediafire.com/download.php?zzg4pjccz0od9uo

CRC32: 5F044C22

MD5: C7F2DDC50DB3E96673977E41CEB643D6

SHA-1: 6966DE005C9E83A968025673B187884E375BB680

The WW update file (thanks for kikistans for uploading):

http://www.mediafire.com/download.php?kzr30e1vufbgee9

CRC32: 954022CD

MD5: C5D117D05399281BAB243B2420D721A8

SHA-1: B063E4ECA70985C66128D81ADF5B4C48383C64FE

The TW update file (thanks for lineager for uploading, and for beckzz for notifying me):

http://www.mediafire.com/download.php?b3jt0m8f7427ix3

or

http://d-h.st/kks (Original link by lineager)

CRC32: 7C828B02

MD5: 9259363BC2A20558ABB635515E979076

SHA-1: FC339F2FB67693D642BC5425E2B0940E152D7D17

The Guide:

Extract the above zip and put the three files on the main storage.

Copy the dlpkgfile to the main storage

Enter shell:

SU

mount -o remount,rw /system

cp /mnt/sdcard/dexdump /system/xbin/dexdump

cp /mnt/sdcard/ps3bttest /system/xbin/ps3bttest

cp /mnt/sdcard/rfcomm /system/xbin/rfcomm

chmod 777 /system/xbin/dexdump

chmod 777 /system/xbin/ps3bttest

chmod 777 /system/xbin/rfcomm

mount -o remount,ro /system

cp /mnt/sdcard/dlpkgfile /cache/dlpkgfile

echo '--update_package=/cache/dlpkgfile' >> /cache/recovery/command

Exit shell.

Shut down tablet.

Turn on while holding the "volume down" key.

When it vibrates, release the power key and keep holding the volume key.

Three lines appear, hit "Volume UP".

Update starts!

Update Finishes!

Additional Notes:

Some users reported success after replacing the build.prop with the one attached here (ripped from the US .28 blob).

Reported several times: It appears that temporarily unrooting through Voodo increases the chances for the update to complete successfully.

Should an attempt to update regularly fail, checking for the update again may result in a "no update for your device" message.

Clearing the app data for CMCLient and DMClient (Settings-> Apps -> All tab) and then checking for updates again is reported to force the update to re-download. Sometimes this has to be repeated for 2-3 times.

Here's a great guide by 1wayjonny for those who still face issues after trying the method listed here. It involves completely wiping the device, but it should also help for those facing the malformed /system/bin folder issues. http://xdaforums.com/showpost.php?p=32113041&postcount=261

3/10/2012: Asus has released the full system images of Jelly Bean. If all else fails (try going through the FAQ first):

http://support.asus.com/Download.aspx?SLanguage=en&p=20&s=16&m=Eee Pad Transformer Prime TF201&os=32

FAQ

Root lost? Check these threads:

http://xdaforums.com/showthread.php?t=1706588

http://xdaforums.com/showthread.php?t=1886460

My update is still failing! How can I get additional help?

Open adb, and type in the following:

su

cat /cache/recovery/last_log

Post the output here.

When posting, it's best to wrap the log in CODE tags, for easier reading.

Common issues found through the update log:

script aborted: assert failed: file_getprop("/system/build.prop"

This is a case of mismatched build.prop file. Replace the build.prop, and try again the steps from cp /mnt/sdcard/dlpkgfile /cache/dlpkgfile onwards.

Command: "/sbin/recovery" | WITHOUT | "--update_package=/cache/dlpkgfile"

The update command was not written successfully. Try the following:

SU

cp /mnt/sdcard/dlpkgfile /cache/dlpkgfile

rm /cache/recovery

mkdir /cache/recovery

echo '--update_package=/cache/dlpkgfile' >> /cache/recovery/command

Now reboot and boot to recovery as described above.

script aborted: assert failed: apply_patch_check("/system/bin/***

Some busybox installers remove the original binaries from system/bin, causing the update to fail. The first to be checked is always gzip, but even after adding it manually the next binary (ip) is reported as missing.

Call to arms! I'm looking for some help in trying to resolve this issue. See this message: http://xdaforums.com/showpost.php?p=32164458&postcount=104

Todo:

Complete FAQ

Looking for all other dlpkgfile for missing variants (TW etc.).

Thanks (in no particular order ):

Wipeout, Bait-fish, 1wayjonny, kikistans, beckzz turboman93, csetera and lineager for helping to form this thread.