Comment 552 for bug 1734147

I have a Z50-70. This was my only fix cause i erased my HDD and wasnt able to boot through any media.
-Bought a USB Bios programmer (Ch341A) and a test clip.
-Took back-up of the ROM from the chip itself.(Chip is right next to PCI-E slot)
-Used UEFI tool to remove and replace the BIOS region which is on the back up file.(you can get the ROM file from BIOS Mods).
-Flashed it back to the chip.
-turned on the system, now it detect all kinds of bootable media

P.S- this was an easy $10 fix, rather than taking it to a service center and replacing the Motherboard.