APFS partition inaccessible
Solution 1:
Well, nobody answered, but I was able to recover my APFS volume. It is important to mention that you have to have knowledge of your partition layout for successful restore. Hybrid MBR spans the entire volume and when I removed the incorrectly positioned volume the Hybrid MBR shrinked down to that point not leaving additional space and I got the error:
gpt add: /dev/disk3: error: no space available on device
I was able to fix it using:
sudo gdisk /dev/disk6
Password:
GPT fdisk (gdisk) version 1.0.5
Partition table scan:
MBR: hybrid
BSD: not present
APM: not present
GPT: present
Found valid GPT with hybrid MBR; using GPT.
Command (? for help): p
Disk /dev/disk6: 1000215216 sectors, 476.9 GiB
Sector size (logical): 512 bytes
Disk identifier (GUID): DF8BA5A4-2A3A-4A1B-9F1F-AA6A6332D9A5
Partition table holds up to 128 entries
Main partition table begins at sector 2 and ends at sector 33
First usable sector is 34, last usable sector is 1000215182
Partitions will be aligned on 8-sector boundaries
Total free space is 999805549 sectors (476.7 GiB)
Number Start (sector) End (sector) Size Code Name
1 40 409639 200.0 MiB EF00 EFI System Partition
2 409640 707245575 337.0 GiB FFFF CATALINA
Command (? for help): x
Expert command (? for help): n
Expert command (? for help): w
Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING
PARTITIONS!!
Do you want to proceed? (Y/N): y
OK; writing new GUID partition table (GPT) to /dev/disk6.
Warning: The kernel may continue to use old or deleted partitions.
You should reboot or remove the drive.
The operation has completed successfully.
That converted from Hybrid to Protective MBR (regular GPT). But still APFS did not have the correct code:
sudo gdisk /dev/disk6
GPT fdisk (gdisk) version 1.0.5
Partition table scan:
MBR: protective
BSD: not present
APM: not present
GPT: present
Found valid GPT with protective MBR; using GPT.
Command (? for help): p
Disk /dev/disk6: 1000215216 sectors, 476.9 GiB
Sector size (logical): 512 bytes
Disk identifier (GUID): DF8BA5A4-2A3A-4A1B-9F1F-AA6A6332D9A5
Partition table holds up to 128 entries
Main partition table begins at sector 2 and ends at sector 33
First usable sector is 34, last usable sector is 1000215182
Partitions will be aligned on 8-sector boundaries
Total free space is 999805549 sectors (476.7 GiB)
Number Start (sector) End (sector) Size Code Name
1 40 409639 200.0 MiB EF00 EFI System Partition
2 409640 707245575 337.0 GiB FFFF CATALINA
So then I was able to issue:
sudo gpt add -i 2 -b 409640 -s 707245575 -t apfs /dev/disk6
/dev/disk6s2 added
sudo gdisk /dev/disk6
GPT fdisk (gdisk) version 1.0.5
Warning: Devices opened with shared lock will not have their
partition table automatically reloaded!
Partition table scan:
MBR: protective
BSD: not present
APM: not present
GPT: present
Found valid GPT with protective MBR; using GPT.
Command (? for help): p
Disk /dev/disk6: 1000215216 sectors, 476.9 GiB
Sector size (logical): 512 bytes
Disk identifier (GUID): DF8BA5A4-2A3A-4A1B-9F1F-AA6A6332D9A5
Partition table holds up to 128 entries
Main partition table begins at sector 2 and ends at sector 33
First usable sector is 34, last usable sector is 1000215182
Partitions will be aligned on 8-sector boundaries
Total free space is 292559974 sectors (139.5 GiB)
Number Start (sector) End (sector) Size Code Name
1 40 409639 200.0 MiB EF00 EFI System Partition
2 409640 707655214 337.2 GiB AF0A CATALINA
Now the APFS restored the correct code AF0A and it reappeared in the disk utility and I could browse my files again.