The EULA usually goes away after you've driven for a short distance above a minimum speed with a good satellite fix.

You're wise to be wary of losing the BC20 use with 2797 firmware. I've been unable to confirm if the stock 2797 has that disabled in it's pinouts to the BC20 cradle/receiver or whether it's disabled in firmware, or maybe it's both [or neither and just a marketing ploy by garmin to not state 2797 and BC are compatible]. But Garmin is Garmin so i guess it's most likely firmware not hardware, or it's neither of them, but surely not both.

If you're game [not much risk, but it'd have to be all yours of course], you could try to flash 2797 fw using the dezl760 boot.bin and maintaining the dezl's HWID of 1516 rather than changing it to 1517 of nuvi2797. That should make it very safe to do and you can flash back very easily and safely too. Then if the BC20 doesn't work, just revert. You'd also be helping to eliminate or confirm firmware as an issue in the supposed incompatibility of the camera with 2797. If you want to try and need more help please ask, i'll make a pack for you if you want. I'd happily do that flash myself if i had access to an RV760 or a dezl760 and a BC20.