Hi I freed the storage of /data ( and /data/media/0 ) using TWRP mkfs. What I did was an advanced wipe with TWRP.

Now I want to override all the free space of /data with garbage to ensure that my data is deleted.

I used this shell script run in a sshDroid terminal.

The problem is when the disk space runs out and I get the error:

The script keeps on running and I suddenly see a lot of free space again:

Just before I got the error I could see 1MB with the df command for the /data mount point.

The size of the output file is also not changing anymore it stays at 4.9GBstrong text:

If I try the same script on an openSuse VM with a 1GB block device sdb1, I do get the desired behavior: Disk is full and error keeps repeating.

Can someone explain me this android behavior ?