I have a 7900 too. I did not find a way around the bios error on reboot either. I am on my phone but in the gnoboot thread there was a post on how to get around the boot issue. I tried it and it worked. I would take a look at that thread.
Pretty sure it was this post...
@Grinroth and others not booting GRUB:
The problem was in the old bios of the HP computer (and probably others) apparantly:
Solved by using these steps:
1) mount the .img (vfat if you're using windows) image
2) use RMprep to prepare the USB stick Fat32 with 2nd partition (USB HDD option) and install Grub4DOS on it. Let it install to MBR and(!) PBR.
3) copy all files and directories from the mounted image into the USB stick
4) open the computer case and UNPLUG the DVD - CD ROM drive (!) without this action the kernel will freak out on ata_piix (!)
5) close the case (duh) set bios to boot from USB, boot from stick and select GNOboot.me at first. Install synology with assistant. Boot alpha at reboot (automatic, so no worry)
done. Some bios roms don't like the USB boot when written directly from the img. This way the bios from HP will boot the zImage, so the Synology DSM can be installed. meh.
Joined: 04 Mar 2014 08:26
Credit to original poster...