SD card shows up as Internal in Disk Utility I recently Installed Sierra on my sandisk 32 GB sd card which was not bootable after I formatted it it shows up as Internal how to I fix this issue?

output of diskutil list:

$ /dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *121.3 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:          Apple_CoreStorage Macintosh HD            120.5 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3

/dev/disk1 (internal, virtual):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS Macintosh HD           +120.1 GB   disk1
                                 Logical Volume on disk0s2
                                 C8FBDE46-9264-4EF1-8287-2AA808659654
                                 Unencrypted

/dev/disk2 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *31.9 GB    disk2
   1:                        EFI EFI                     209.7 MB   disk2s1
   2:                  Apple_HFS SD CARD                 31.6 GB    disk2s2
You cannot back it up if the partition information is damaged. You first need to repair the damage. Sounds like it is the root/boot disk, which means you don't want to try using it. 

Yes you can boot your damaged Mac into Target disk mode by pressing the T key right after powering it on. Then plug it into another Mac. The damaged disk will appear as a drive on the good Mac. Run diskutil to repair your damaged disk.