I also can’t get to my devices physically to update via USB, and I am having this problem as well. Has anyone else been able to get this to work?
I flashed part1 and part2 OTA from the CLI, got “Flash device OK: Update started” for both. Tried flashing my code (from Particle Dev, presumably targeting 0.5.0 by default) and the Electron went into safe mode so I reset and reflashed system binaries OTA and got the same responses and then, as @ScruffR suggested, I flashed Tinker from Build with 0.4.8 (On device) targeted but it has not updated to 0.5.0 and again when I flash my code it still goes back to safe mode.
I’m not really sure how to look into this any further, is there any way to get verification that the system firmware is updating from the OTA flash? It doesn’t seem that the update is actually happening even though the flash call from the CLI returns a success message.