Lenovo Y700 How to Enable BIOS Downgrade

Posted on 5th Nov 2016 10:06:30 in Laptops

First Failure

The first attempt was to simply run the BIOS install for the version i wanted to FLASH, the snag is that the tool does not let you flash a BIOS that is older than the currently installed BIOS.

Bios Downgrade Error


Digging Deeper

Not one to give up easily and determined to revert to the older BIOS.

  • First Extract the BIOS you want to flash (WinRar is what i used)
  • In the extracted directory their is a file called "platform.ini"
  • Edit platform.ini and change the line "CheckByBios=0" to "CheckByBios=1" save the file
  • Run the BIOS flash utility from the extracted folder "H2OFFT-W.exe"

The tool will then allow you to flash the older BIOS over the newer one.

CheckByBiosErrorMessage="This BIOS file is not allow to flash. The flash process will be terminated."
;This flag is the switch of checking BIOS version.
;Flag (dwsDWS)
; default : 2.
; 0 : Don't check rom file version.
; 1 : Check BIOS version.
; When rom file version is older than BIOS, it will display
; a warning message and close application.
; 2 : Depend on BIOS report.
;CheckByBios (dwsDWS)
; default : 0.
; 0 : Normal process.
; 1 : It will pass version by IHISI to BIOS and check by BIOS.
; When BIOS return not allow to flash, it will be terminated the process.
; When BIOS allow to flash, it will go ahead and do it's normal process.
; When this flag is enable but BIOS not support, it will skip version check and assume allow to flash.
;CheckByBiosErrorMessage (dwsDWS)
; default : "This BIOS file is not allow to flash. The flash process will be terminated."
; String : User defined error message when BIOS is not allow to flash this version image.