Comment # 6 on bug 1083037 from Jiri Srain

Well, the generic code is written to MBR:

bootloader/mbr_update.rb:66 Copying generic MBR code to /dev/sda
bootloader/mbr_update.rb:52 mbr type = gpt
lib/cheetah.rb:158 Executing "/bin/dd bs\=440 count\=1
if\=/usr/share/syslinux/gptmbr.bin of\=/dev/sda".
lib/cheetah.rb:206 Error output: 1+0 records in
lib/cheetah.rb:206 Error output: 1+0 records out
lib/cheetah.rb:206 Error output: 440 bytes copied, 0.00296738 s, 148 kB/s
lib/cheetah.rb:178 Status: 0

Can you check the contents of your MBR? Use the MBR code in the file as above.

And, please, check whether your BIOS tries to load system from the right disk
and whether it supports GPT partition tables.