Select MBR for legacy BIOS and create the USB drive. Use rufus to create the Windows 10 64 bit USB installer. Select the “Install/Update custom coreboot firmware” option. Please check your CPU before flashing the BIOS. Please remove the write protect screw before flashing the BIOS. Warning: this BIOS is only for the Acer C720, C720P, HP Chromebook 14, Toshiba CB-30, and Dell Chromebook 11. Acer C740, Acer C910, Acer CB5-571, Toshiba Chromebook 2 and Dell Chromebook 13, see here: Click Flash Custom Coreboot BIOS