I upgraded to JB without being rooted, now want root but i'm not ready to unlock bootloader yet. After reading the guide here and seen it requires unlocked bootloader i tried another approach.
WARNING: As always there is a chance something may go wrong... If you do it i'm not responsible for bricks, do it on your own risk.
WARNING: This will wipe your data
WARNING: As with all updated make sure your battery is charged
This is what i did:
1. download .30 firmware from asus site that matches your SKU
2. extract the zip file to the root of your microSD card
3. rename extracted file (ex: US_epad-user-220.127.116.11.zip as mine is US SKU) to EP201_768_SDUPDATE.zip
4. insert sdcard and power off tablet
5. press power+voldown, release them after it starts and press volup within 5 seconds to enter stock recovery
6. working android displayed .................. wait patiently to finish update...........
I think this method is peaty safe as is a normal update, no fastboot, root or unlocked bootloader.
I sincerely thought asus recovery will skip the update because is a lower version then the one installed but it did not.