Boot not found - gigabyte bios

Hello
I have been using Endless OS for years.
I had to replace the motherboard and CPU.
It is now a Gigabyte B650 Eagle.

The bios doesn t find the endless boot. I see the sata ssd, but it doesn t recognize the boot.
I havé read about UEFI and secure boot options but i can t solve this.

Do you Know how to fix this

Thank you

I

I have read some solutions on the forums and youtube about the BIOS, but none worked. I asked a return of the MB, so don’t bother racking our brains on this too.

You could try solving this by creating a super grub disk:

I don’t know how old is your Endless OS system. But, if the system is old and still use MBR partition, then new UEFI only mother board cannot detect the boot partition probably. (I guess)

Another possibility: the older shim is not trusted by the UEFI/BIOS’ dbx. Endless OS’ shim had been updated and signed by Microsoft for renew. So, the new mother boards UEFI/BIOS only accept the new Endless OS shim.

Of course, some more other possibilities …