SanDisk File System Help

Hello,

I can't mount two separate SanDisk cards. Both were connected by a buddy to an Android phone via a cheap card reader and both were able to be viewed the first time. Now they don't show up on macOS High Sierra, Windows 10 or any phones. Both have images that we need to get but I can't figure out how to get macOS to see the data.

When I insert the card into my air I get the message. "The disk you inserted was not readable by this computer." Ignore Eject

Anybody know what steps I should take next?

Here are the responses I get now from terminal and first aid.

diskutil list

/dev/disk2 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: FDisk_partition_scheme *7.9 GB disk2

1: DOS_FAT_32 7.9 GB disk2s1

mount /dev/disk2

mount: /dev/disk2: unknown special file or file system.

first aid

Repairing file system.

Volume is already unmounted.

Performing fsck_msdos -y /dev/rdisk2s1

** /dev/rdisk2s1

Invalid BS_jmpBoot in boot block: 555342

File system check exit code is 8.

Restoring the original state found as unmounted.

File system verify or repair failed.

Operation failed…