I am sure I've gotten in way over my head with this, and I'm pretty sure you've all seen this before, but is there a way to go back to my original TP-Link Archer C2600 firmware?
Please prepend your topic title with the device name, to help categorizing this post as reverting back to the vendor firmware is highly device specific.
Looking at it -I don't own the device in question, so re-check my suggestions- it should work quite easily via debricking. There are probably easier approaches using mtd directly, but this would need checking and documenting by someone owning the device in question.