I don't know what invokation of lsblk you're using. When I run lsblk on my machine, I get
something like this:
ham:~$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
nvme0n1 259:0 0 238.5G 0 disk
├─nvme0n1p1 259:1 0 1G 0 part /boot
├─nvme0n1p2 259:2 0 228.7G 0 part /nix/store
│ /
└─nvme0n1p3 259:3 0 8.8G 0 part [SWAP]
Not seeing any 'data' parts in the TYPE column, there. If I run `lsblk -f` (to show
filesystem information):
NAME FSTYPE FSVER LABEL UUID FSAVAIL FSUSE% MOUNTPOINTS
nvme0n1
├─nvme0n1p1 vfat FAT32 87C7-181E 768.7M 25% /boot
├─nvme0n1p2 ext4 1.0 7ec00b9f-e09d-4c0d-af55-34b2f412e3bf 71.4G 63% /nix/store
│ /
└─nvme0n1p3 swap 1 swap 0d462dac-ca81-4f49-a1f9-d9c1b0f3323c [SWAP]
I'm seeing filesystem designations in the FSTYPE column. My intuition would indicate that
if you're just seeing 'data' in the FSTYPE column, there's not a filesystem that lsblk
could recognize. Can you give us more information about your card? Dump the first sector
or so to see what filesystem headers there are, if any?
In the mean time, you can make a full disk backup with dd so you can format the card and use
it in other capacities. In order to do that, you'd probably do something like this:
sudo dd if=/dev/your_sd_card_here of=./your_sd_card.img bs=1M
Make sure that you have enough storage space on the medium holding that disk image backup.
Hope this helps,
Ryan
https://beepboop.systems