Pinephone pro seems to have died overnight....

[projectcato]

Received my Explorer Edition yesterday. Booted it, played around. Everything seemed fine, Discover seemed broken (default KDE Manjaro). Shut it down, tried mounting it in the pinephone keyboard, never got the keyboard working, planned on trying the pogo shim this weekend. Shut it down, back into "phone mode" played around some more. Let it charge, then unplugged it and left it on my desk for the night.

This morning, wouldn't start. Plugged in, off to work. Still no boot. Removed battery, monkeyed around with various attempts at powering up. I don't get a vibration or anything on plugging it in as described charging indicator (pine64.org) . 

Next steps for troubleshooting?

I didn't notice this before: PinePhone Pro - PINE64 (blue box):

If the battery is fully drained U-Boot might fail to boot any installed operating system on the eMMC and microSD card due to a bug.
If that's the case please start your phone in Maskrom mode and let it charge in that for a few hours. To do that:

• Remove any microSD card from the phone
  
• Hold the "RE" button underneath the back cover of your Explorer Edition (or shorting the bypass contact points on the Developer Edition)
  
• Connect the phone to an USB port of a computer, while still holding the button
  
• Check if the phone in Maskrom mode appears in the output of the Linux command 
  
  
  Code:

  lsusb
   on the computer (if the device disappears again please use a different cable)
  
• Let the phone charge for multiple hours.
  

Can confirm this worked for me, got up to about ~30% charge by the time I got impatient and tested. Note, after this procedure, the phone only booted after another battery remove / reinstall.