Dual boot Odyssey X86 after firmware upgrade SD-BS-CJ41G-300-101-F

Updated bios firmware on Odyssey X86 and can no longer get grub menu to display. Have the Odyssey with emmc and windows, and nmve ssd with debian installed. Tried to sudo update-grub2, checked grub.cfg, and tried install of other distros - still no grub menu. Grub errors when trying to install on mmcblk0,1,2,3,or 4 (the emmc). Grub did install and work fine on nmve0 (the ssd sata) prior to firmware (F) update. I could go back to firmware SD-BS-CJ41G-300-101-K, but that version lacked stability and crashs after 10 to 15 minutes with no solution there. Firmware (F) gives better stability but still crashes. Haven’t used windows long enough to comment on stability and emmc. Anybody having these problems?

I could not get a proper boot from grub install on the ssd mbr. Easiest fix is to make a small 1st partition of type GPT (or GUID) on the ssd and make a directory /boot/efi. Install linux distro on the ssd and tell it to install grub on that partion. The firmware is UEFI and will find and load grub when you boot that partition. Not sure why not legacy bios support.

There’s is a bios option for compatibility. You shouldn’t need that though. Does your mmc have the efi partition as well? It’s best to be the first partition and no more than 512mb. Post an ‘sudo fdisk -l’

Mike1 thanks for the reply. I had finally got it to work and work well by not installing grub in that first 512 bytes of any drives. The legacy and efi compatibility setting in bios (or whatever its called now) would not find grub and menu there no matter which drive medium. I didn’t go through log files. I created a 5 mb msdos partition on both nmve and m.2 ssd, installed grub on them flagged as efi partitions and can now boot from both. Very happy with my little computer now but still locks up. Don’t know the cause of that. Again thanks.