Please note that the "readbyte 16" error indicates serial communication trouble and is unrelated to 3.0.

I'd be checking the serial cable for frays, etc... I was having the weirdest problems with the serial stuff at one time, and discovered it was just a cable that had gone bad (frayed at the flex point).

Also, were you using the last build of Logoedit? We fixed some bugs in upload.exe that might have caused the readbyte 16 error in earlier versions.

The reason the player wouldn't boot is that it erased the flash but never finished filling it up with the new kernel.