How to boot back to EUFI from Legacy BIOS, pressing F2 getting "Operating System not found"

I have an Acer V5 571 touch running Windows 8, I went to the BIOS and changed from boot EUFI mode to Legacy BIOS mode and disable secure boot. When rebooted, i got the F2 / F10 prompt, selected F2 (BIOS setup) but did not go to the BIOS settings, instead it looks like it went ahead and tried booting an OS then started getting "Operating System not found" error. All the Windows 8 partitions stil exists, looks like windows 8 doesn't boot with Legacy BIOS mode, so I would like to change the boot mode back to EUFI but cannot do so since i cannot access the BIOS. Any help is much appreciated.