Did you or the previous owner do a firmware upgrade recently ? Your text is the same as his at the very end. #8 and #15 devices not detected. Start with post #30 in this thread: Professional - P3Pro - Firmware Update Mistake
Here you will find not only instructions to blindly follow, but an explanation of what you're really doing. Fixing is also preceded by diagnosis - this is how all repairs should look like. So, here is the link to my DM365 chip reflashing tutorial, with specific tasks performed on GL300 RC...
phantompilots.com
I saw this on the search. Looks like you have the same issue with 8 and 15 code not detected. Not sure if my link is the same topic as above, but do a search and you will see many have had the same issue, some reporting back that that they sorted the issue following the instructions. Hope it helps.