How to install RW_LEGACY in Dell Chromebook 11 3189/3180 (KEFKA)

A RW_LEGACY firmware allows your Chromebook to boot third-party OSes without removing write protection or getting rid of ChromeOS, which can be pretty useful for old EOL Chromebooks like this one. In this guide, I'll show how to install an alternative bootloader for your Dell Chromebook 11 3189/3180.

Prerequisites

Chromebook in Developer Mode
Root shell access
A compatible RW_LEGACY file for your Chromebook

Backup your firmware

Don't skip this step, make sure to make a backup of your current firmware in case if anything goes wrong. Open up a shell and type:

sudo flashrom -p host -r backup.rom

Flashrom should make an 8MB dump of your stock firmware. If it errors, you are probably in a directory you are not allowed to write to. Go to a different directory and try again.

Please make multiple copies of your ROM file (like your cloud storage, different flash drive, etc.), this could save your laptop if you mess up.

Download RW_LEGACY firmware

You can download the firmware from MrChromebox servers here. This is the file you will need to flash. Check its checksum, it should be any of these below:

SHA512: a1b2b5ef29bb70e2b8228ecd36f084b7362a1116b15081818c9e778ab95889401996c6e73cabfe6bddd931cb5def549b72820dd8311e382e4e76c1e33fc1c72d
SHA256: 58bf9a2707786efff8d60e77c09ba31f50f07ed119f4a7b6f2b7426329e832ee
SHA1: fc05925858625124a31d67b8db13867bb9741218
MD5: 2af34c48132b4952aaabc84e5b1dcf3d

Flash RW_LEGACY region

Enter:

sudo flashrom -p host \
  --fmap \
  -i RW_LEGACY:seabios-bsw-mrchromebox_20180912.bin \
  --noverify-all \
  -w

and wait for it to finish flashing. it should output "SUCCESS". This command only updates the RW_LEGACY region in your firmware with a valid one, we don't need to flash the entire ROM.

Flashrom syntax may vary between different versions, I recommend using the latest ChromeOS supported by your Chromebook.

Enable booting from alternative bootloader

Run:

sudo crossystem dev_boot_altfw=1

or for older systems:

sudo crossystem dev_boot_legacy=1

That's it! Now reboot your Chromebook and press CTRL+L on the developer mode boot screen, you should boot from USBs now!