From unlock to after flashing. To revitalize a old tablet.

Step 1: unlock

  • The system has build (Android 4.2)
  • Install Unlock tool v8 from Asus
  • Delete Google account from Android as the unlock tool cannot compare the Google password anymore
  • Run unlock tool, and let it remove the device
  • During reboot, it shows message that it is being unlocked

Step 2: move to fastboot mode

  • power it down
  • hold power + vol down key to power it up again
  • It shows “RCK”, android, and “wipe data” icons
  • now the device is in “fastboot” mode (as indicated by the message at top left corner)

Step 3: TWRP for recovery

$ fastboot devices
015d15b4d723ee12        fastboot
$ fastboot -i 0x0B05 flash recovery twrp_tf300t_kang_2.8.7.2.img
sending 'recovery' (7126 KB)...
OKAY [  2.762s]
writing 'recovery'...
OKAY [  7.874s]
finished. total time: 10.636s
$ fastboot reboot

finished. total time: 0.020s
  • Now the device has a stock ROM with custom recovery image

Step 4: Make a backup before flashing

  • Power down the device again and boot it up to fastboot mode once more
  • With “RCK” icon flashing, push vol up button. The device should say “Booting recovery image”
  • Then TWRP is being loaded
  • Make a backup from TWRP, backup is at sdcard/TWRP directory and only the system, no user data
  • The backup I see is 2255MB
  • After back up, select “Reboot”

Step 5: Installing a ROM

  • Obtain from from
  • ROM of choice =
  • Other packages to download:
    • Gapps:
    • Latest SuperSU:
    • Sound improvements & misc : K.A.T_V2.1.0.apk
  • Copy KatKiss, gapps to sdcard
  • Unplug USB cable, boot into recovery mode (power+vol down, then vol up on RCK)
  • Wipe data for factory reset
  • Install, find the zip file for KatKiss, and confirm with that
  • After install, alsow wipe cache and dalvick cache partitions
  • Then install the gapps zip in similar way
  • Then reboot
  • Need to wait for some time at first boot
  • Then configuration from scratch

Post installation

  • KatKiss doesn’t work well with external SD cards
  • Used Cyanogenmod CM12 instead
  • Install apk failed in CM12, then needed to turn on developer mode, run adb shell, then:
su # to get root
pm set-install-location 1 # to install to internal instead of auto
chmod 777 /data/local
chmod 777 /data/loca/tmp  # fix permission problem
pm install /storage/sdcard1/  # do the install
exit # leave root
  • Install by pm install must be in /storage/sdcard1 instead of /mnt/media_rw/sdcard1 because only the former is readable by non-root (the user of pm)