ASUS Fonepad K004 (ME371MG) is an older device that officially stopped at Android 4.1.2, a useful feature of installing a in 2021—typically via unofficial builds like LineageOS —is the extended device longevity . Key Feature: Extended Device Longevity

But for a brief moment in 2021, when Asus had abandoned it years earlier. And in the world of custom ROMs, that’s a victory.

: Stock Android 4.1.2 is no longer compatible with most modern apps like YouTube or Duolingo. A custom ROM allows you to run newer API levels required by these apps.

"My SIM card isn't detected after flashing." Fix: Reboot to TWRP, wipe Cache/Dalvik , then flash the Modem_Firmware_K004_2020.zip . The 2021 ROMs use an older RIL base.

— Move apps to the SD card using Link2SD or App2SD.

Flashing a new ROM formats your internal storage. Back up all photos, contacts, and documents to a PC or cloud storage before proceeding.

: Development for this specific model has largely ceased. Most users looking to revive this tablet in 2021 focused on rooting it to remove bloatware and using "Lite" versions of apps rather than full custom ROMs. Essential Pre-Flashing Information

Swipe to confirm the backup. Copy this backup folder to your PC for safekeeping. Step 3: Wipe Existing Data

: You can still root the device using legacy tools like Magisk or SuperSU to remove pre-installed "bloatware" and potentially improve performance slightly.

Modern apps require newer APIs. Custom ROMs allow you to run versions of Android that support contemporary applications.

If you still wish to attempt a modification, the standard procedure for older ASUS tablets typically involves: ASUS Fonepad - Support

Flash the recovery image using the following command: fastboot flash recovery twrp-k004.img