Cave with no/new battery fails to boot on 2609.x

Bug Reports Firmware Bugs
1

System Details

  • Device: Cave (Asus C302c)
  • OS: Chrome OS Flex on eMMC / LMDE7 via USB
  • Firmware Type: UEFI Full ROM
  • Firmware Version: 2609.2 (also tried 2609.1)
  • Internal storage type: eMMC

Summary of the Issue

Will not boot without battery, screen and keyboard just flash every couple seconds, then reset and repeat.

I have a bad battery, and have been attempting to replace it. I have tried 3 replacement batteries from 2 different vendors, with 2609.x the laptop fails to boot at all, never get to the coreboot logo, it fails and resets after about 2 seconds and repeats this pattern, all you see is the display backlight and keyboard backlights come on, then it immediately resets. If I put my bad swollen battery back in, it boots normally. If I remove the battery cable, it fails to boot with the 2 second bootloop. If I reinstall 26.06.1 I can boot with the new batteries (they are not charging) and I can also boot with the battery cable disconnected.

Steps to Reproduce

  1. Install new discharged battery, or disconnect battery

  2. Install 2609.x firmware

  3. reboot

Expected Behavior

Laptop should recognize and charge new battery and reboot to OS normally - none of those 3 options happen on 2609.x I have reinstalled and rolled back 3x, same symptom every time.

2

booting without a battery is not a supported feature on many devices. I’m pretty much out of space on these older ECs to do much of anything.