I fixed the jam, and restarted the printer, everything seemed to be normal. The printer went through a startup routine, cleaning heads and what-not, but when it finished the error persisted.
I restarted the machine, and still, the error remained. After a bit of googling, I found the solution:
How to RESET the Error code “6502”
1 – Unplug your printer, pausing for effect.
2 – Plug the printer back in and then:
2a – Press AND HOLD the Power button
2b – Press the Stop button twice
2c – Release the Power button
2d – Press the Stop button a further four times (see notes)
– someone reported you may hear beeping, I did not
– I think the four button press of the stop AFTER releasing the Power button may not be required since once the powerbutton was released, the system immediately went into a startup routine, it didn’t appear to wait for the stop buttons. But who knows, it was there, I did it, and it worked