How to debug ets_loader.c errors - ESP32-C6 (Adafruit Feather C6) has boot loop with ets_loader.c 67

[tyeth]

Hi, the same sketch builds fine and flashes fine locally. When instead building in CI the device boot loops with:

15:12:17:072 -> ESP-ROM:esp32c6-20220919
15:12:17:072 -> Build:Sep 19 2022
15:12:17:073 -> rst:0x7 (TG0_WDT_HPSYS),boot:0xb (SPI_FAST_FLASH_BOOT)
15:12:17:073 -> Saved PC:0x4001a9f4
15:12:17:073 -> SPIWP:0xee
15:12:17:073 -> mode:QIO, clock div:2
15:12:17:075 -> load:0x4086c410,len:0xcf8
15:12:17:085 -> ets_loader.c 67 

This is with debuglevel verbose. I'm hoping someone has some ideas to try, or ways of debugging this.
I've tried flicking flash memory mode (DIO/QIO) as that was a previously similar issue.
The fully qualified build name + flags are here: https://github.com/adafruit/ci-arduino/blob/ci-wippersnapper/all_platforms.py#L21
Also here with an unmodified toolchain (same result): https://github.com/adafruit/ci-arduino/blob/master/all_platforms.py#L21
esp32:esp32:adafruit_feather_esp32c6:CDCOnBoot=cdc,CPUFreq=160,FlashFreq=80,FlashMode=qio,PartitionScheme=min_spiffs

Related issue: adafruit/Adafruit_Wippersnapper_Arduino#636

[brentru]

@VojtechBartoska Could you please take a look at this, thanks!