Advice needed - Locked OEM 1 Pc Tonneau Cover

A couple weeks back I decided to fix the loose linkage on the Toyota OEM 1pc fibreglass tonneau cover.
Decided to machine up some proper bushings, and while at the local fastener store, I removed the factory bushings from the linkages, and then stupidly closed the cover. Of course, now with the linkages disconnected there is no way to open it.
Did some digging, but still not sure if I can remove the lower tailgate hinge bracket bolts to swing the tailgate out from the bottom. If anyone knows if this is possible, it would be much appreciated.

 

Well, since no responses, I’ll go ahead and remove the rear bumper to see if removing the lower tailgate pivot brackets will permit me to lower the tailgate to access the tonneau cover linkage.
Only -13C (9F) out…

 

Had a peak under the rear bumper and noticed both rear quarter panel braces had rusted away where they meet the bed. Truck has been oil sprayed from new, but I guess you need to monitor this kind of stuff. Already ordered from local dealer. They’ll be in on Monday.

 

Got the rear bumper off thinking there might be bolts securing the pivot joint for the tailgate, but seems there are none. I thought I had seen some bolts while surfing the interweebs. Need to figure out how that joint is secured to the tailgate and if the hardware is accessible.
Pic is looking up at the bottom PS of the tailgate.

 

Did some more digging, and looking at the design of the hinge piece, there are screws /bolts that are on the vertical side of the tailgate which I cannot access. So, the idea of removing the tailgate by removing the hinge is a no go.
Next option is to grind off the six bolt heads that secure the tonneau cover at the hinges. Not even sure that if I do that, it will lift up enough to squeeze under it to get inside the box to access the linkage. Damn!

 

Decided to drill a hole in the cover. Started in one spot and hit something, so moved back a bit which ended up being a good thing as I would have hit the latch mechanism if I drilled in the first spot. Had to use a magnetic on a telescoping tip to get the PS rod up where I could grab and pull on it. Didn’t see the DS rod through the hole I had drilled, and after prying up the PS of the tonneau cover to get a peek at the DS lock, I noticed the rod was not one the locking mechanism. D’oh! So, grabbed a 4’ pc of extruded aluminum I had, put a small threaded screw thru the end, and poked around until U hooked the lever on the locking mechanism. Doing all this this with no power at the house, a crappy but expensive O-Light flashlight, and freezing temps. Just glad it’s over with for now. Will look at patching up the hole in the spring.