Asus P320 WM 6.5 back to WM 6.1 (downgrade)

If you try to use the normal procedure to downgrade WM 6.5 back to official ROM 6.1, you may see the following errors:

 

I have try to update, but it show the followings message when boot up.

BTLR 3.1
Start SD init
Get MBR success
can't find galaxymini-ond.raw!
can't find 850_GAX_SD.bin!
can't find FLASH.BIN!
can't find GSM.BIN!
can't find GSM.RAW!
can't find EXT_ROM.NBO!
Init SD download fail!

 

The solution at the following:

 

Backup all your files / data / contacts because everything gets wiped clean (e.g. PPCPimBackupV2.8_wm2005).

Downgrade procedure:
1. After downloading the office rom form Asus e.g. P320_V4_15_0_V4_10_V1_28_0_ZHH, unzip it

2. Open the folder “2577” and find the file “850_GAX_SD_Enc.bin” and rename it to “850_GAX_SD.bin”

3. Copy folder “2577” into the root directory of your micorSD card. Insert microSD card into P320 after the copy

4. Keep the battery in charge during upgrade procedure

5. Run the “AutoRun.exe” in the WM 6.5, waiting it complete.

6. Press and hold Volume Down key (on left side, shown below) and poke reset button (on bottom side), the system will boot up. Then release reset button and continue to hold Volume Down key until the screen shows writing percentage

7. The system will start installation automatically

8. It will re-start when system installation is completed

9. System will start upgrading after touch panel calibration and date/time setting

Asus P320 WM 6.5 back to WM 6.1 (downgrade)