Boot Linux from USB on a ChromeOS machine

[cyberquarks]

I have a USB with Linux on it [specifically: https://www.ncomputing.com/products/vSpace/LEAF%20OS] that I need to boot on a Intel-based Chromebook laptop. The USB is bootable as it boots from the USB of my desktop PC.

I managed to set up developer mode from my Chromebook from this guide: https://www.youtube.com/watch?v=UWXO61_v_xo&t=7s to hopefully boot the USB from my Chromebook.

All went well except that I cannot boot from USB when on the "OS Verification" screen, the only command that works is CTRL + D which boots Chrome OS but CTRL + L does not do anything other than to hang/freeze the screen.

My question is, what is the latest way to boot a Linux USB from the USB port on a Chromebook? Note that I don't refer to dual-booting just booting from USB.

Also, from what I see the RW_LEGACY is loaded in my Chromebook:

```
 ChromeOS Device Firmware Utility Script [2020-12-22]
 (c) Mr Chromebox <mrchr...@gmail.com>
*********************************************************
**   Device: HP Chromebook x360 11 G1 EE (SNAPPY)
** Platform: Intel ApolloLake
**  Fw Type: Stock ChromeOS w/RW_LEGACY
**   Fw Ver: Google_Snappy.9042.253.0 (06/30/2020)
**    Fw WP: Enabled
*********************************************************
**      1) Install/Update RW_LEGACY Firmware
**      2) Install/Update UEFI (Full ROM) Firmware
** [WP] 3) Set Boot Options (GBB flags)
** [WP] 4) Set Hardware ID (HWID)
*********************************************************
Select a menu option or
R to reboot  P to poweroff  Q to quit
```

[dragon788]

I believe RW_LEGACY installs SeaBIOS which is an MBR only bootloader and in order to boot newer distributions that are EFI style you will need to potentially chain load an EFI aware boot loader.

--
--
Chromium OS Discussion mailing list: chromium-...@chromium.org
View archives, change email options, or unsubscribe:
https://groups.google.com/a/chromium.org/group/chromium-os-discuss
---
To unsubscribe from this group and stop receiving emails from it, send an email to chromium-os-dis...@chromium.org.

[cyberquarks]

Hi, thanks for the tip, so that that mean that I need to run the Mr Chromebox script e.g. the Option 1 to Install/Update RW_LEGACY Firmware? Or something else?

[dragon788]

Yes, you'll probably want the updated/fixed RW_LEGACY from MrChromebox and you'll want to set the `crossystem` options for legacy and USB booting.

[Denny Lockhart]

Just to add, legacy booting is now referred to as 'altfw' and the crossystem command has changed.

Here are my settings for USB, legacy/altfw, and signed-only flags:

sudo crossystem |grep dev_boot

dev_boot_altfw          = 1                              # [RW/int] Enable developer mode alternate bootloader

dev_boot_signed_only    = 0                              # [RW/int] Enable developer mode boot only from official kernels

dev_boot_usb            = 1                              # [RW/int] Enable developer mode boot from external disk (USB/SD)