Just wanted to add that after a bad flash, i too had a completely blank core with nothing except the tiny (D7) blue led flashing intermittently.
I tried the “factory reset” - but the first few times i tried it it didn’t work, but eventually it did.
I’m re-writing the instructions here in case it helps anyone understand the process better:
- Keep the MODE & RST buttons pressed down together (the tiny blue LED will be constantly lit)
- Release the RST button but – continue to keep the MODE button pressed
- Wait a few seconds
- The main LED will start to flash Yellow – continue to keep the MODE button pressed
- The main LED will go blank – continue to keep the MODE button pressed
- The main LED will turn solid white – continue to keep the MODE button pressed
- The main LED will start to flash white – you can finally release the MODE button!
Your spark should start flashing blue now.
Don’t forget, you’ll need to re-connect your core to Wifi (using the “+” button in the app) just like you did when you first got it…
Cheers,
R