Cannot recover from undervolting failure with new firmware 2026.04.09 on Asus CN60

System Details

  • Device: panther beltino ASUS CN60 Chromebox
  • OS: Linux
  • Firmware Type: UEFI Full ROM
  • Firmware Version: 2026.04.09
  • Internal storage type: mSATA

Summary of the Issue

Cannot recover from undervolting failure with new firmware

Steps to Reproduce

  1. Flash current 2026.04.09 MrChromebox firmware using script

  2. Successfully reboot into firmware setup

  3. Choose a modest 100mv undervolt for CPU & cache

  4. Save & reboot

  5. Black screen; no UEFI/rabbit display; assume due to undervolting settings. Power LED is ON, fan full speed. HDMI display blank.

  6. Unsuccessful in resetting UEFI NVRAM settings with PwrButton + Esc, F2, or Recovery button above Kensignton lock (still get black screen at boot)

Expected Behavior

Respectfully requested: A working reset to defaults method without requiring flashrom for recovering from bad values entered in NVRAM; such as a key combination I missed in the FAQ or test points to short on the CN60 motherboard to clear the NVRAM settings.

I did find a BoardView schematic:

https://drive.usercontent.google.com/download?id=1-G9vWYAYAz6QRM23esUE65zIk5jIu3tb&export=download&authuser=0

there’s no shortcut key to reset the NVRAM currently, and the boardview really doesn’t help in any way. erasing the NVRAM via a USB flash programmer is the only option ATM