diskutil verifyVolume disk3s2
Started file system verification on disk3s2
Verifying file system
Volume is already unmounted
Performing fsck_hfs -fn -x /dev/rdisk3s2
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
sudo gpt show disk3
start size index contents
0 1 PMBR
1 1 Pri GPT header
2 4 Pri GPT table
6 76800 1 GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B
76806 121861142 2 GPT part - 48465300-0000-11AA-AA11-00306543ECAC
121937948 158693
122096641 4 Sec GPT table
122096645 1 Sec GPT header
sudo gpt add -b 121937948 -s 158692 -t 426F6F74-0000-11AA-AA11-00306543ECAC -i 3 disk3 ; diskutil list disk3
diskutil mount disk3s3 ; diskutil list disk3
Volume on disk3s3 failed to mount
If the volume is damaged, try the "readOnly" option
/dev/disk3 (external, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *500.1 GB disk3
1: EFI EFI 314.6 MB disk3s1
2: Apple_HFS 499.1 GB disk3s2
3: Apple_Boot 650.0 MB disk3s3
diskutil verifyVolume disk3s3
diskutil info disk3s3
Device Identifier: disk3s3
Device Node: /dev/disk3s3
Whole: No
Part of Whole: disk3
Volume Name: Not applicable (no file system)
Mounted: Not applicable (no file system)
File System: None
Partition Type: Apple_Boot
OS Can Be Installed: No
Media Type: Generic
Protocol: USB
SMART Status: Not Supported
Disk / Partition UUID: 31BC1CD8-1A6B-420F-814C-772964E04114
Partition Offset: 499457835008 Bytes (121937948 4096-Byte-Device-Blocks)
Disk Size: 650.0 MB (650002432 Bytes) (exactly 1269536 512-Byte-Units)
Device Block Size: 4096 Bytes
Read-Only Media: No
Read-Only Volume: Not applicable (no file system)
Device Location: External
Removable Media: Fixed
sudo gpt remove -i 2 disk3
sudo gpt add -b 76806 -s 121861142 -t 53746F72-6167-11AA-AA11-00306543ECAC -i 2 disk3 ; diskutil list disk3