rootfs corruption after using ext4write

Hi everybody, i hope someone can help me out here. I have been following a tutorial (on PentesterAcademy). This about BeagleBone Block. So at one point the student is supposed to use ext4write to write data from memory to to a new file on the rootfs partition. However after doing so the rootfs partition is corrupted. I did the following steps

  • setenv autoload no

  • tftpboot 0x80000000 (the address is the start address of the DRAM, the output confirms the command was executed successfully).

  • ext4write mmc 0:3 0x80000000 /bin/

load file into memory

V-Boot=> tftpboot 0x80000000 rootkit
link up on port 0, speed 100, full duplex
Using ethernet@4a100000 device
TFTP from server; our IP address is
Filename 'rootkit'.
Load address: 0x80000000
Loading: ###
	 1.7 MiB/s
Bytes transferred = 34639 (874f hex)

write file to rootfs

V-Boot=> ext4write mmc 0:3 0x80000000 /bin/rootkit 0x874f
File System is consistent
update journal finished
34639 bytes written in 1440 ms (23.4 KiB/s)

if i use reset command after that then it wont boot up due to rootfs corruption. in the video tutorial he does the same steps and i wonder if there is some step inbetween missing that needs to be done in order to not corrupt the rootfs partition.

would be great if someone has an idea and could help me out here.

p.s.: i also tried the same with the save command but the result was the same.

U-Boot 2018.01 (Mar 02 2018 - 01:36:21 -0800)

BeagleBone Black:
CPU : AM335X-GP rev 2.1
Model: TI AM335x BeagleBone Black

What version of U-Boot?


Hi, it is a very old version. according to the output at bootup it is
U-Boot 2018.01 (Mar 02 2018 - 01:36:21 -0800)

ext4 has had extensions added since then… Retry with our latest branch:

(you might still need to enable extwrite, as i don’t think i enable it by default…)