Partition showing as 'FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFF'; attempted to fix it but made it worse MacBook Pro 2015. I recently dual-booted my Mac with Linux for school however I changed my mind on which distro to run and figured the best way to change would be to format and remove the Linux partitions and start over.      

After I formatted the partitions I attempted to remove them but only one could be deleted and it turned into one 24.4gb partition which would give me an error everytime I tried to delete it and merge the partition back into a single Macintosh HD volume. I also noticed my boot volume was showing as 'ahfs' and not 'apple_boot' and my Macintosh HD volume was showing as 'FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFF' so I followed a guide to change the boot drive back to 'apple_boot' and attempted to follow this guide (Data Not Backed Up, Partition Type: FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF) and made it to gpt add -i 3  -b 188093184 -s 1269536 -t 426F6F74-0000-11AA-AA11-00306543ECAC disk0           

This command returned erorrs: 

gpt add: disk0: Suspicious MBR at sector 0    
gtp add: disk0: error: no space available on drive     


I researched ways to fix it and came up with this solution,    

gpt destroy /dev/disk0         


but received an error of suspicious MBR at sector 0 so I removed the hybrid MBR with

fdisk -i -a hfs /dev/disk0 


and received 

fdisk: could not open MBR file /use/standalone/i386/boot0: No such file or directory 

ATTENTION - UPDATING MASTER BOOT RECORD 

Do you wish to write a new MBR and partition table? [n] 


I entered y
and received no confirmation.

I then tried to add back my partitions with     

gpt add -b 40 -s 409600 -i 1-t C12A7328-F81F-11D2-BA4B-00A0C93EC93B /dev/disk0 


and received the erorrs:

gpt add: error: bogus map
gpt add: unable to open device '/dev/disk0': Undefined error: 0


Now when I am stuck with both the bogus map and undefined error 0 error everytime I attempt gpt show or gpt add.

Is there anyway to recover my data? I went to go get my backup HDD out of the office but my little brother had dropped it in soda a few weeks ago and told no one so it's useless. Any tips would be greatly appreciated!
The disk lost any gpt partition in the partition table because the secondary GPT mismatched the primary GPT (and its CRC was wrong) and thus was bogus.

To recover everything the following was done:


boot to a working external macOS boot disk
get the details:

diskutil list
gpt -rvvv show disk0
fdisk /dev/disk0
diskutil umountDisk0

completely zero out the 1st and 2nd GPT and the MBR:

dd if=/dev/zero of=/dev/disk0 count=34 bs=512
dd if=/dev/zero of=/dev/disk0 seek=(size_of_disk_in_blocks-33) count=33 bs=512

create a new gpt:

gpt create -f /dev/disk0 

add all partitions

gpt add -i 1 -b 40 -s 409600 -t C12A7328-F81F-11D2-BA4B-00A0C93EC93B disk0

a hexdump of block 409640 revealed a CoreStorage partition - a pic taken by the OP before, suggested a size of 187683544 blocks for the second partition:

gpt add -i 2 -b 409640 -s 187683544 -t 53746F72-6167-11AA-AA11-00306543ECAC


the volume verified with 0 errors and had to be unlocked: the volume is encrypted!
Tried to restore a previous recovery partition:

gpt add -i 3 -b 188093184 -s 1269536 -t 426F6F74-0000-11AA-AA11-00306543ECAC
diskutil verifyVolume disk0s3


No file system was detected; the diskutil verifyVolume command failed. The recovery partition and its content was deleted previously. The third partition has to be removed again:

gpt remove -i 3 disk0

Since the recovery partition - usually containing an intermediate FV key required while booting to FV - is missing, the main volume was reverted to HFSJ:

diskutil cs list #get the lvUUID of the main volume
diskutil cs revert lvUUID #old (admin) password needed to unlock the volume

The volume was expanded

diskutil resizeVolume disk0s2 0
diskutil verifyVolume disk0s2

Booted to the restored and expanded main volume the system (Sierra 10.12.6) was reinstalled to restore the missing recovery partition.
Re-enable FileVault.