Encryption requires that 16KiB remain unused by the filesystem on the userdata partition. You can check if this is the issue by
adb logcat > android.log on a computer
- enable developer options first
- you might need to root, I don't think so though
- Start the encryption process in settings
If this is the problem, you'll see the following in the logs:
E Cryptfs : Orig filesystem overlaps crypto footer region. Cannot encrypt in place.
To fix this issue, you'll need to resize your userdata partition.
If it's ext4, I believe that you can use
resize2fs to do this. I'm not sure how to do this though.
If it's f2fs, the process is quite a bit more involved:
Reboot into TWRP. Do
adb shell on a computer.
fdisk -l /dev/block/sda to view the partition structure. You'll see something like this:
Logical sector size: 4096
Disk identifier (GUID): 98101b32-bbe2-4bf2-a06e-2bb33d000c20
Partition table holds up to 16 entries
First usable sector is 6, last usable sector is 14145530
Number Start (sector) End (sector) Size Code Name
1 6 7 8192 0700 ssd
2 8 8199 32.0M 0700 persist
3 8200 73735 256M 0700 cache
4 73736 73991 1024K 0700 misc
5 73992 74119 512K 0700 keystore
6 74120 74151 128K 0700 devcfg
7 74152 74183 128K 0700 devcfgbak
8 74184 74311 512K 0700 frp
9 74312 76871 10.0M 0700 oem_dycnvbk
10 76872 79431 10.0M 0700 oem_stanvbk
11 79432 79687 1024K 0700 param
12 79688 81711 8096K 0700 reserve1
13 81712 85759 15.8M 0700 reserve2
14 85760 85887 512K 0700 config
15 85888 14145530 53.6G 0700 userdata
Make a note of:
- the "Logical sector size"
- the partition number for userdata
- the start sector for userdata
- the end sector for userdata
Make a backup of this partition. You will lose the data on it if you don't, it will be explicitly wiped. I believe that TWRP has a function to do this, but I used a tarball &
~ # mount /dev/block/sda15
~ # tar -cpzf /mnt/fs.tar.gz /mnt/
tar: removing leading '/' from member names
tar: /mnt/misc/camera/cam_socket2: socket ignored
tar: /mnt/fs.tar.gz: file is the archive; skipping
adb pull /mnt/fs.tar.gz
Unmount the partition using
Next, wipe part of the existing filesystem to make sure that we don't get any warnings when making the new filesystem:
dd if=/dev/zero of=/dev/block/sda<partition number> bs=1M count=128. This is the point of no return.
Create a new filesystem using the numbers you wrote down from before: calculate
partition_size = end_sector - start_sector - (16384 / logical_sector_size) manually, and make a note of that number.
mkfs.f2fs /dev/block/sda<partition number> <partition_size> to create a new partition of the appropriate size.
Mount it, and use
adb push fs.tar.gz /mnt/ to send over your backed up data.
cd /mnt; tar -xf fs.tar.gz; mv mnt/* .; rm -rf mnt fs.tar.gz to extract, and you're done!
Restart and retry encrypting! Hopefully everything will work.