I previously installed Windows (on a partition in the main SSD, sharing it with High Sierra) on a mid 2011 21,5 inch iMac using this guide.
Afterwards I installed Big Sur using opencore legacy patcher on a secondary HDD I have on the machine. I decided to remove Windows and replace it with Big Sur, so I went ahead and tried to delete bootcamp partition using bootcamp assistant from High Sierra, it didn't detect the Windows partition so I rebooted to Big Sur and used its bootcamp assistant, the process failed with a message saying that the disk couldn't be restored or something like that, unfortunately I can't recall properly.
Since then, the High Sierra partition can't be booted/mounted/repaired and I'd like to keep my data without having to format the disk and reinstall High Sierra into it (I'm keeping a High Sierra partition because it's the last supported mac os version my machine has)
I'll leave the output of some commands that might be useful:
✘ juan@iMac-de-Juan ~ diskutil list
/dev/disk0 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *500.1 GB disk0
1: EFI EFI 209.7 MB disk0s1
2: Apple_HFS 239.6 GB disk0s2
(free space) 260.3 GB -
/dev/disk1 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *1.0 TB disk1
1: EFI EFI 209.7 MB disk1s1
2: Apple_APFS Container disk2 817.6 GB disk1s2
3: Apple_APFS Container disk3 182.1 GB disk1s3
(free space) 268.4 MB -
/dev/disk2 (synthesized):
#: TYPE NAME SIZE IDENTIFIER
0: APFS Container Scheme - +817.6 GB disk2
Physical Store disk1s2
1: APFS Volume Disk2 601.3 GB disk2s1
/dev/disk3 (synthesized):
#: TYPE NAME SIZE IDENTIFIER
0: APFS Container Scheme - +182.1 GB disk3
Physical Store disk1s3
1: APFS Volume Big Sur - Datos 13.9 GB disk3s1
2: APFS Volume Preboot 283.2 MB disk3s2
3: APFS Volume Recovery 626.2 MB disk3s3
4: APFS Volume VM 1.1 MB disk3s4
5: APFS Volume Big Sur 32.6 GB disk3s5
6: APFS Snapshot com.apple.bless.D393... 32.6 GB disk3s5s1
juan@iMac-de-Juan ~ sudo gpt -vv show /dev/disk0
Password:
gpt show: /dev/disk0: mediasize=500107862016; sectorsize=512; blocks=976773168
gpt show: /dev/disk0: PMBR at sector 0
gpt show: /dev/disk0: Pri GPT at sector 1
gpt show: /dev/disk0: Sec GPT at sector 976773167
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 468049344 2 GPT part - 48465300-0000-11AA-AA11-00306543ECAC
468458984 508314151
976773135 32 Sec GPT table
976773167 1 Sec GPT header
juan@iMac-de-Juan ~ sudo diskutil verifyVolume /dev/disk0s2
Password:
Sorry, try again.
Password:
Started file system verification on disk0s2
Verifying file system
Volume is already unmounted
Performing fsck_hfs -fn -x /dev/rdisk0s2
File system check exit code is 8
Restoring the original state found as unmounted
Error: -69845: File system verify or repair failed
Underlying error: 8
Thanks in advance
edit:
✘ juan@iMac-de-Juan ~ sudo dd if=/dev/disk0s2 bs=64 count=1 | hexdump -Cv
Password:
1+0 records in
1+0 records out
64 bytes transferred in 0.002769 secs (23113 bytes/sec)
00000000 8d 9d 91 54 9d 84 bd 1a 01 00 00 00 00 00 00 00 |...T............|
00000010 3b 56 52 00 00 00 00 00 01 00 00 80 00 00 00 00 |;VR.............|
00000020 4e 58 53 42 00 10 00 00 b8 bb 7c 03 00 00 00 00 |NXSB......|.....|
00000030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
00000040