I have a Galaxy S10e running crDroid 13. I don't have TWRP on it (since it had to be installed from the custom LineageOS recovery), but https://stackoverflow.com/questions/29442630/copy-full-disk-image-from-android-to-computer explains how to get partition images usind adb pull.
Which partitions do I need to back up for a "complete" backup, though? ls -la /dev/block/by-name shows many:
boot -> /dev/block/sda14
bota0 -> /dev/block/sda1
bota1 -> /dev/block/sda2
bota2 -> /dev/block/sda8
bota3 -> /dev/block/sda24
cache -> /dev/block/sda28
cp_debug -> /dev/block/sda30
cpefs -> /dev/block/sdd1
dqmdbg -> /dev/block/sda22
dtb -> /dev/block/sda12
dtbo -> /dev/block/sda13
efs -> /dev/block/sda3
keydata -> /dev/block/sda21
keyrefuge -> /dev/block/sda20
keystorage -> /dev/block/sda6
misc -> /dev/block/sda19
nad_refer -> /dev/block/sda17
omr -> /dev/block/sda29
param -> /dev/block/sda4
persistent -> /dev/block/sda18
product -> /dev/block/sda27
radio -> /dev/block/sda16
recovery -> /dev/block/sda15
sda -> /dev/block/sda
sdb -> /dev/block/sdb
sdc -> /dev/block/sdc
sdd -> /dev/block/sdd
sde -> /dev/block/sde
sec_efs -> /dev/block/sda7
steady -> /dev/block/sda9
system -> /dev/block/sda25
uh -> /dev/block/sda10
uhcfg -> /dev/block/sda11
up_param -> /dev/block/sda5
userdata -> /dev/block/sda31
vbmeta -> /dev/block/sda23
vendor -> /dev/block/sda26
I don't know what most of them do, e.g. bota, cpefs, etc. I suppose I need boot, system, recovery and userdata, but what else?
It's also unclear to me where user files on "internal storage" (/sdcard) are stored. userdata is mounted as /data, but I don't see /sdcard listed in the output of mount. It does show this:
/data/media on /mnt/runtime/default/emulated type sdcardfs (rw,nosuid,nodev,noexec,noatime,fsuid=1023,fsgid=1023,gid=1015,multiuser,mask=6,derive_gid,default_normal)
/data/media on /mnt/runtime/read/emulated type sdcardfs (rw,nosuid,nodev,noexec,noatime,fsuid=1023,fsgid=1023,gid=9997,multiuser,mask=23,derive_gid,default_normal)
/data/media on /mnt/runtime/write/emulated type sdcardfs (rw,nosuid,nodev,noexec,noatime,fsuid=1023,fsgid=1023,gid=9997,multiuser,mask=7,derive_gid,default_normal)
/data/media on /mnt/runtime/full/emulated type sdcardfs (rw,nosuid,nodev,noexec,noatime,fsuid=1023,fsgid=1023,gid=9997,multiuser,mask=7,derive_gid,default_normal)
but I don't understand how that works, because /data/media seems to be a regular directory and not a device file.
/sdcardchanged from a real sdcard to an emulated one it is simply a directory on the user data partition. And the sdcard directory is just a soft link in the file-system. Just look at it usingls -l /to see the link targets.userdatashould actually include all user data then. @alecxs Ah maybe that explains why I cannot open the userdata image using the Linux Disks utility! It detects an ext4 filesystem, but fails to mount it with a generic error ("cannot mount /dev/loop0 read-only (udisks-error-quark, 0)"). I have stock ROM files, but don't know how to get the partition names from those. It's just the standard AP, BL, CP, CSC and HOME_CSC tar files.userdata, which obviously does need to be backed up. So I'm not sure how this tells me which partitions to back up.adb fastboot boot twrp.imgand doing backups from TWRP would be a better option, after all.