Check it out here if you were left stuck with the other methods. http://forum.xda-developers.com/showthread.php?t=1427838 - Get Razorclaw and install it, no root needed.- Get the recovery installer and do the same.- Check your version info. You'll see a pair of letter which are like the "WW", "UK", "US" pairs in the various update files. It appears, at least when I was trying to do this, that you cannot use unmatched pairs (I don't know about the "WW" one, since I started with US and (accidentally) went to .13 US version).- Follow the instructions regarding downloading the .13 update (WW version and/or whatever letter pair your tablet uses, in case the WW doesn't work). Unzip, slap on external SD, power off, power on with down volume, volume up to go to recovery, bang. Done.- Do the same thing with the megaupload file (.19). The second option did fix the problem I had, which was trying to update to a WW.19 firmware from a US.13 - DO THE DOUBLE FILE/RENAME TRICK. It works perfectly.- Run razorclaw, run recovery installer, and gloat.Seriously, now knowing how the paired-letters-not-compatible-with-other-letters thing works, the whole process would take maybe 10-15 minutes tops. Thanks for the post!I have a UK transformer and I lost root after the OTA 8.6.5.21 update. Yes, should have checked before applying.Wasn't able to root with NVFlash so I downloaded http://www.multiupload.com/X65RBVD2MB the 8.6.6.19 file that was posted by Lizard here http://forum.xda-developers.com/show...1393953&page=3 I unzipped it until I had the WW_epad-user-8.6.6.19.zip file. I placed this on the root directory of the external SD card and when I rebooted it gave me the option to install.This installed OK so I just re-ran Razorclaw and sorted. I have superuser back.. This would seem to be the US update but is working fine on my UK B70 (presumably SBK2 pad). I've installed CWM and backed up too. No promises that this won't destroy your pad/steal your gal or boy/shoot your dog.1) Download http://www.multiupload.com/X65RBVD2MB 2) Unzip so you have just have WW_epad-user-8.6.6.19.zip. Keep this zipped and copy to root of external micro SD.3) Reboot with card in place, don't enter recovery.4) When it booted back into the OS I had a triangle in the notification bar. I clicked this and it offered to install the update.5) After tab updated as usual I just re-ran Razorclaw and I had root back.1) Download http://www.multiupload.com/X65RBVD2MB 2) Unzip so you have just have "WW_epad-user-8.6.6.19.zip". Keep this zipped and copy to root of external SD.3) Put another copy of the same file on your external SD card and name it "EP101_SDUPDATE.zip"4) Put both files "EP101_SDUPDATE.zip" and "WW_epad-user-8.6.6.19.zip" on the root of your internal SD card.5) Power down your TF6) Power up into recovery - by pressing the power button and volume down button. Then press volume up when instructed by the screen.7) You should now see the Android guy with some gears turning. This is good, actually this is GREAT! This will go on for a minute or so and then the device will reboot on its own. It will then go to the boot screen and you should see a bar showing you the progress of the update.8) Once it has completed, install RazorClaw and root your device.For those not able to get it working, a few things to check.1-Make sure you actually extract the WW_epad-user-8.6.6.19.zip within the zip. Inside the file you download is an Asus folder, inside that is an Update folder, inside that is the WW_epad-user-8.6.6.19.zip file you'll be working with.2-When renaming, if your PC is set to "hide known extension", you'll not see the .zip so if you type in .zip you'll get filename.zip.zip The file manager on the TF should show you the extension3-Make sure it's on the root of the sd card and not within any folder.4-Check spelling of filesWW_epad-user-8.6.6.19.zip EP101_SDUPATED.zip5-Micro sd card is in FAT32 format. Try a different card or format again (after saving your stuffs)6-File manager on the TF sdcard is internal and Removable/MicroSD is the external sd card.It would be useful for people to report info with posts about success or not. What SBK, serial number (B70 etc) and current firmware are you on? I'm no dev but hopefully we can make things easier for others.Resources http://forum.xda-developers.com/show....php?t=1346180 Gnufabio's recovery installer, suggested by Baseballfanz Reboot to Recovery Makes it easier to enter recovery after installing CWM.Please let me know if any info is missing and I'll update.