Trying to unbrick TEEMO Chromebox

Support General Device Support
1

System Details

  • Device: TEEMO (ASUS Chromebox CN62)

  • OS: ChromeOS Flex (booting from USB)

  • Firmware Type: Stock

  • Firmware Version: Google_Fizz.10139.117.0

  • Internal storage type: eMMC

Summary of the Issue Cannot install ChromeOS Flex to internal disk. MrChromebox firmware-util.sh fails with “Could not get I/O privileges (Operation not permitted)” / “Programmer initialization failed”. Device was enterprise-enrolled (Cognizant). Developer Mode is active, WP screw removed. Running script from ChromeOS Flex Live USB (board detected as “reven” instead of “teemo”). Ubuntu USB does not boot via Ctrl+U or Ctrl+L (SeaBIOS gives 2 beeps).

Steps to Reproduce

  1. Boot ChromeOS Flex from USB (Ctrl+U in Developer Mode)

  2. Open crosh → shell

  3. Run: cd; curl -LO mrchromebox.tech/firmware-util.sh && sudo bash firmware-util.sh

Expected Behavior Script should detect TEEMO hardware and allow firmware flashing.

2

ChromeOS Flex doesn’t support running the firmware-utility script, boot another distro.

Why are you wanting to run Flex on TEEMO anyway? you’ll lose the headphone jack.

3

Hi MrChromebox, thanks for the response.

The device is enterprise-enrolled (managed by a former employer). The goal is not specifically ChromeOS Flex — the goal is to unenroll/free the device from enterprise management so it can be used normally. ChromeOS Flex was just the approach we were trying.

The main blocker is that we can’t boot any alternative distro to run your script:

Ctrl+U only boots ChromeOS Flex from USB (works)

Ctrl+L gives 2 beeps — SeaBIOS doesn’t boot

We ran sudo crossystem dev_boot_altfw=1 but it still gives 2 beeps

Ubuntu 22.04 and 26.04 both tried with MBR and GPT via Rufus, neither boots

WP screw has been removed. Developer Mode is active. The script fails from ChromeOS Flex with the I/O privileges error as expected.

Is there a way to get Ubuntu or another distro to boot on TEEMO via Ctrl+L or Ctrl+U? Or is the CH341A external programmer the only remaining option?

4

if developer mode is not blocked, why are you not simply running the script from ChromeOS?

5

The internal disk was wiped accidentally during troubleshooting (ran dd if=/dev/zero of=/dev/sda bs=512 count=1), so the device no longer boots from internal storage. It only boots via ChromeOS Flex USB.

We also no longer have access to the original ChromeOS on the internal drive. Is there a way to restore the internal ChromeOS so we can run the script from there? Or can the script be run from the ChromeOS Flex USB in a different way?

6

yes, that’s what the ChromeOS recovery tool is for. the device literally links you to it when it boots to recovery mode (ChromeOS is missing/damaged)

7

If you do not have another computer go to cros.tech and download the recovery image for your board and flash it from your phone using an adapter and etchDroid on Android

8

Thank you thank you, I could do it with this option, I installed chrome os flex, just to test it and it works fine, but you were right about the headphone jack that doesn’t work. Which OS do you recommend instead?

9

Linux and Windows both work decently well, any distro should work OOTB. might need the weirdtreething audio script for headphone jack functionality