Extract files from Chrome OS / Chromebook recovery image

Question

My Problem: I am trying get hold of the official Chrome WideVine CDM plugin for an ARM architecture.

My Understanding So Far: Given ARM-based Chromebooks can stream Netflix (and Netflix uses the WideVine CRM plugin), I am lead to believe a Chrome OS installation should contain the files I'm after. As I don't have access to an ARM-based Chromebook, my next best is a Chromebook recovery image.

Where I'm up to: I have downloaded a HP Chromebook 11 recovery image, chromeos_6812.88.0_daisy-skate_recovery_stable-channel_skate-mp.bin, from here (the HP Chromebook 11 is ARM-based)

What I'd like to do next: Extract two files from the recovery image.

Note: I don't have access to an ARM based Chromebook to just copy the files from :/

Does anyone know how I could do such a thing?

Answer 1

The .bin file is just a disk image that contains many partitions. You can "load" the image by running sudo kpartx -av chromeos_6812.88.0_daisy-skate_recovery_stable-channel_skate-mp.bin (the -v is for verbose mode). This will load 12 partitions (from /dev/mapper/loop0p1 to /dev/mapper/loop0p12) and make them available for mounting, and you should see some additional drives in your file manager.

In this case, the partition you're looking for is labelled ROOT-A, and corresponds to the third partition (/dev/mapper/loop0p3). For some reason, opening it in my file manager directly didn't work, so I had to mount it manually by running sudo mount -t ext2 /dev/mapper/loop0p3 -o ro /media/saikrishna/chromeos/. This will mount the ext2 partition in read-only mode in the /media/saikrishna/chromeos directory (change the last part to an existing empty directory on your system).

To remove the mappings, run sudo kpartx -dv chromeos_6812.88.0_daisy-skate_recovery_stable-channel_skate-mp.bin. If that doesn't print out anything (which was the case for me), run sudo kpartx -dv /dev/loop0.