How to fix MP Compact4 boot up in Orange LED and not respond to Feed button? How to fix MP Compact 4 corrupt firmware problem? MP Compact MK III Orange Light Flashing
Send the firmware with a serial cable. Use the grey serial cable that is supplied with each printer, and this will only work using COM1 on the PC.
Use Tera term and set the Baud rate to 38400bps in the program.
Connect to the printer. Possible you see some commands from printer to Host.
Send firmware again. Sometimes it takes 3-5 tries before it can succeed.
Note: Do confirm if your printer is running DPL or Label point and download the firmware accordingly. Firmware section weblink: https://www.datamax-oneil.com/do/com/en-us/home/support-downloads/downloads-drivers&p=2BB20CAA-0771-84D1-EF96FA5358213BEF#SM1 Tera Term - http://www.datamax-oneil.com/do/com/en-us/file.cfm/teraterm-4.74.zip?contentID=7555&ext=.zip