My Phone won't Turn On

[andrewmv]

Checking the battery directly, looks like there is still 2.8vDC charge on it. So there's some life there still.

NO NO, there is no life there at all !

The battery must never go below 3.0V !

As the OS'es is rather experimental for the phone, they might not yet have
checks built in, that should shut the OS down when reaching 3.0V - so keep it
in a charger for now.

OK, so it's been sitting on a charger (Nintendo switch: 5.0v 1.5a; 15.0v 2.6a) for the better part of 3 hours with no charging light and no improvements on the condition. So either there's life there and no booty or no life and no chargey... The battery was at 50% when I started experiencing problems... Additionally, nothing happens while plugged in.

I can try to pick up a charger for exactly what's specified, but I highly doubt that's going to change anything.

I'm also experiencing this problem - I received the phone and confirmed the factory test booted, slapped Ubuntu Touch on an SD card, and it ran without issue. After about an hour, I did a soft reboot from within Ubuntu to try to sort out a camera issue, and then it never turned back on again, even when connected directly to the charger.

I was able to run the factory test directly off this charger before I'd realized there was factory tape over the battery terminals, so I don't suspect battery issues.

I completely re-flashed the SD card with the Ubuntu Touch image that had worked correctly before, no change. I tried pressing and 10-second holding that recessed RESET button while connected to power, this also hasn't changed anything.

I figured the next troubleshooting step would be to hook up the serial console, so I flipped DIP switch #6 to the off position, and built a headphone jack TTL serial cable using a CH340 interface, wired according to the Wiki documentation. This also gives me no input or echo as I attempt to power-cycle the device, but it's very difficult for me to test if my serial cable is actually working correctly.

The only sign of life though this entire process was, the first time I connected the serial headphone jack plug, the phone's flashlight turned on for about ten seconds. I can find no documentation on what this means, and I haven't been able to recreate the behavior.

Any ideas on next troubleshooting steps?

Minor update - I apparently had the RX/TX pins swapped on my homemade TTL adapter, and now I *am* able to get an error message on the serial console:

Code:

U-Boot SPL 2019.04-01015-g8dacfcdc32 (Dec 19 2019 - 11:56:34 +0000)
DRAM: 0 MiB
### ERROR ### Please RESET the board ###

Holding reset for 10 seconds doesn't do anything more than repeat the message - and the timestamp never moves.