# Chrome OS - Brunch - Recover after a failed update
In case if update fails / is not applied correctly when following 
https://github.com/sebanc/brunch#update-only-the-brunch-framework the following steps can be done to recover 
the brunch installation.  

<b>NOTE: These steps are from the developer `sebanc` himself.</b>

## Requirements
1. A linux environment (installed or from live USB). Also knowledge of linux terminal and usage of `dd`.
2. The latest chrome os recovery image from https://cros-updates-serving.appspot.com/.
3. The brunch release from https://github.com/sebanc/brunch/releases.

## Procedure
1. Open a terminal.
2. Locate the place where the chrome os image `chromeos.img` is. You can use any file explorer.
3. `cd` to that path in the terminal.
4. Mount the chrome os image as loop device number 99.
   ```
   sudo losetup --partscan /dev/loop99 chromeos.img
   ```
5. Check if all the partitions are listed by using `lsblk`. The output should be something like:
   <pre>
   /run/.../src/oses >>> sudo losetup --partscan /dev/loop99 chromeos.img          
   [sudo] password for src: 
   /run/.../src/oses >>> lsblk                                                     
   NAME        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
   <i>loop99        7:99   0    29G  0 loop 
   ├─loop99p1  259:0    0  19.8G  0 part 
   ├─loop99p2  259:1    0    32M  0 part 
   ├─loop99p3  259:2    0     4G  0 part 
   ├─loop99p4  259:3    0    32M  0 part 
   ├─<b>loop99p5  259:4    0     4G  0 part </b>
   ├─loop99p6  259:5    0   512B  0 part 
   ├─<b>loop99p7  259:6    0     1G  0 part </b>
   ├─loop99p8  259:7    0    16M  0 part 
   ├─loop99p9  259:8    0   512B  0 part 
   ├─loop99p10 259:9    0   512B  0 part 
   ├─loop99p11 259:10   0     8M  0 part 
   └─loop99p12 259:11   0    32M  0 part </i>
   </pre>
6. Extract the recovery image (in .bin format). Rename it to `recovery.bin`.
7. Mount to as loop device number 100.
   ```
   sudo losetup --partscan /dev/loop100 recovery.bin
   ```
8. Just like step 5, check the partition using `lsblk`. The whole list should be like:
   <pre>
   /run/.../src/Stuff >>> sudo losetup --partscan /dev/loop100 recovery.bin        
   /run/.../src/Stuff >>> lsblk                                                    
   NAME         MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
   loop99         7:99   0    29G  0 loop 
   ├─loop99p1   259:0    0  19.8G  0 part 
   ├─loop99p2   259:1    0    32M  0 part 
   ├─loop99p3   259:2    0     4G  0 part 
   ├─loop99p4   259:3    0    32M  0 part 
   ├─loop99p5   259:4    0     4G  0 part 
   ├─loop99p6   259:5    0   512B  0 part 
   ├─loop99p7   259:6    0     1G  0 part 
   ├─loop99p8   259:7    0    16M  0 part 
   ├─loop99p9   259:8    0   512B  0 part 
   ├─loop99p10  259:9    0   512B  0 part 
   ├─loop99p11  259:10   0     8M  0 part 
   └─loop99p12  259:11   0    32M  0 part 
   <i>loop100        7:100  0     3G  0 loop 
   ├─loop100p1  259:12   0   8.2M  0 part 
   ├─loop100p2  259:13   0   512M  0 part 
   ├─<b>loop100p3  259:14   0   2.3G  0 part </b>
   ├─loop100p4  259:15   0    32M  0 part 
   ├─loop100p5  259:16   0     2M  0 part 
   ├─loop100p6  259:17   0   512B  0 part 
   ├─loop100p7  259:18   0   512B  0 part 
   ├─loop100p8  259:19   0    16M  0 part 
   ├─loop100p9  259:20   0   512B  0 part 
   ├─loop100p10 259:21   0   512B  0 part 
   ├─loop100p11 259:22   0     8M  0 part 
   └─loop100p12 259:23   0    32M  0 part </i>
   </pre>
9. Use `dd` to flash `loop100p3` (i.e. partition 3 from recovery image) to `loop99p5` (i.e. partition 5 from corrupted chrome os image).
   ```
   sudo dd if=/dev/loop100p3 of=/dev/loop99p5 status=progress
   ```
10. Extract the `rootc.img` file from the brunch release.
11. Use `dd` to flash the `rootc.img` file to `loop99p7` (i.e. partition 7 of corrupted chrome os image).
    ```
    sudo dd if=rootc.img of=/dev/loop99p7 status=progress
    ```
12. All done. Unmount both the loop devices.
    ```
    sudo losetup -d /dev/loop99
    sudo losetup -d /dev/loop100
    ```
14. Finally, reboot and boot into chrome os as usual.