Troubleshoot

ERROR: Prompt not detected - upload failed. Trying to recover...

http://forum.espruino.com/conversations/289212/

Instability

If a lot of extra circuitry is connected to the Espruino, it is possible that the USB power is not sufficient to power everything and the Espruino runs unstable, giving intermittent errors. Connect a separate 3.3 V power supply to pin 3.

SD card reinsert

http://forum.espruino.com/conversations/253121/

Problems after save()

Error message:
Uncaught SyntaxError: Got ?[255] expected EOF at line 1 col 1 ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ?[255] ^ in function called from system
http://forum.espruino.com/conversations/297591/

to see what is in flash run
dump()
To clear
reset()
E.setBootCode()
save()
Then test with
dump()
and change
Save on Send Direct to Flash
to
Save on Send To RAM (Default)

Program runs in Web IDE but stalls as stand-alone

Remove console.log and print calls

illegal character

special hyphen allows string to go over a line, but causes error in module if minified.
Disable minification to prevent error.