Okay well this is a tricky one. Maybe I can assist. I just fixed a MFC-J6710DW with the exact issue.

Can I ask did you try and change anything in maintenance mode.? I assume you did and now you can get out of it.

How the 6710DW was fixed was with an Ether net cable + USB and wifi. Yes all 3. Long job turned horrible.

1st estabilish you have wifi connected to the router VIA opening your web browser and confirming its IP address in the router. mine was 192.168.1.13.
Then conencted ethernet and the next address in the router was 192.168.1.14.
Then...

Query, what is this about a Cratridge dump... May I ask what happened exactly. Did printer heads stop working entirely and system throw out problems claiming needing new cartridges.?

I have read previous remarks on another post requesting same thing.

Someone was kind enough to forward there attachments. However, those attachments bricked my printer. I only installed the 25Q64 and left 25Q16 alone. Or should i do BOTH bios's....

Needless to say, what other software tricks can i use. I did try computer USB direct link to flash BIOS firmware update and well again bricked the printer.

Yes i did make a backup...

Any advice would be great if an experience on this printer can be given, Thanking you.