DownGrade Android 9 to 8.1

longthk19longthk19 Level 1
edited September 2020 in ZenFone Max Series

Please tell us some basic information before asking for help:

  1. Model Name: ZB570TL
  2. Firmware Version: Version WW-16.02.1905.435
  3. Rooted or not: not

Hi, I downgrade like your instruction. www asus com/support/FAQ/1040827/

(space= . )

But it is stucked at Step 6 with error :

Support API: 3

::Failed to mount /sdcard: Invalid argument

Couldn't mount /sdcard/

Installation aborted.


  • edited May 2020

    Hi longthk19

    Thank you for your asking. Kindly provide the information below so that we could better assist you.

    1. Could you try with another MicroSD card? Make sure that your MicroSD card is clean or doesn't have any storage issue. To avoid any incomplete downloads, please re-download "Version Android P downgrade to O" via PC.

    #ZB570TL Firmware Spot

    2. Make sure that the download file is put into the root directory of the MicroSD card. (The most outside place you could put into the MicroSD card.)

    If the situation remain the same, could you provide me a video about how you downgrade your phone with MicroSD card?

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