MBP (A1398) will not boot due to not being able to mount internal SSD. Disk utility indicates it is an issue with the EFI partition. Booting from an external drive, here’s what I’ve tried so far:
diskutil repairDisk /dev/disk0
… ** /dev/rdisk0s1 Invalid BS_jmpBoot in boot block: c0fb8b File system check exit code is 8 Updating boot support partitions for the volume as required Creating a new EFI system partition Problems were encountered during repair of the partition map Error: -69764: Couldn't repair the partition map because a new EFI system partition couldn't be created
Unable to enter single-user mode on machine
No valid block 1 on /dev/disk0
sudo gpt -r show /dev/disk0 start size index contents 0 1 PMBR 1 1 Pri GPT header 2 32 Pri GPT table 34 6 40 409600 1 GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B 409640 976695384 2 GPT part - 7C3457EF-0000-11AA-AA11-00306543ECAC 977105024 3 977105027 32 Sec GPT table 977105059 1 Sec GPT header
From my research it seems like GUID partition is incorrect, but not entirely sure best method to resolve. Any suggestions?