May be you should try this method if the remote upgrade from Windows or Mac seems to fail!
Download the firmware (.bin) file, refer to support page for the printer.
Create a folder named ‘DWLD’ on the USB memory device (FAT formatted).
Store the software download file (.bin) in the ‘DWLD’ folder
Switch off the machine, Insert the USB memory device (rear of the printer).
Simultaneously press then hold down the Home and Power buttons until the device powers on and SPECIAL BOOT MENU appears,
Simultaneously touch the letters A in SPECIAL, B in BOOT and the Home button. Do not hold any of the three locations, just touch/press then release simultaneously
At the keypad screen enter code number: 6789#. The SPECIAL BOOT MENU 1/3 screen will display.
Select Download Mode on SPECIAL BOOT MENU 1/3, then touch YES. The UI will display SW update progress. The machine will eventually reboot several times
You can find a video on Youtube for a similar printer that would show you the steps. Search for "Xerox C & B AltBoot"
Thank you for using the Support Forum. Please make sure you have the latest firmware and are following the directions for installing the firmware. If the problem contiunes please consider contacting your support centre again for further assistance.
So, I had a perfect working 6515 when purchased in 2017, but for some reason updated the firmware which caused the scanner to stop being advertised to any PC after a print job had been sent. This required another firmware upgrade to try and resolve and then another which reduced the occurance of this issue. (support were very little help - in the end stating it a known problem = they had no idea, and lost interest)
Problem is every time I turn on / restart the printer it seems to reboot an extra time for each time I have upgraded the firmware, as if it loads them serially reather than just loading the lastest version. I would have assumed the old version would be overwritten like anyother controller with replaceable firmware?
For example I just installed the lasted version, which is the 4th FW upgrade and the printer goes through the loading process including the musical chime it makes 4 times until it is ready for me to try and print. very weird!
Does anyone else have this issue with the 6515?