Easy downgrade, no hardware mod and just typing some easy command in command prompt. The stupid Lenovo tries to prevent you guys to downgrade BIOS.
1. Download BIOS update file ver2.6 (.exe) from Lenovo (https://support.lenovo.com/us/en/downloads/ds029187-bios-update-utility-bootable-cd-for-windows-10-64-bit-81-8-7-32-bit-64-bit-xp-thinkpad-x230-x230i)
2. Execute the downloaded file.
3. You will get an error saying like 'system number does not match blah blah blah'. Just exit the program.
4. Go to C:\DRIVERS\FLASH\g2uj17us just created
5. Go to command prompt, winflash64.exe /sd /file C:\DRIVERS\FLASH\g2uj17us\G2ETA0WW\$01D3000.FL1
6. The computer will reboot and flash the version you want accordingly.
You have to use BIOS ver2.6 to remove the whitelist checking.
