grub: Firmware stalls instead of booting GRUB
22.2 Firmware stalls instead of booting GRUB
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The EFI implementation of some older MacBook laptops stalls when it gets
presented a grub-mkrescue ISO image for x86_64-efi target on an USB
stick. Affected are models of year 2010 or earlier. Workaround is to
zeroize the bytes 446 to 461 of the EFI partition, where mformat has put
a partition table entry which claims partition start at block 0. This
change will not hamper bootability on other machines.
Info Catalog
grub: GRUB only offers a rescue shell
grub: Troubleshooting