I'm hoping that you've also bought the DC20 reversing camera for your US dezl760. It isn't offered with the BC20 reversing camera in the box afaik, unlike the RV760 which can be bought with or without the camera. The camera is offered as an accessory to both dezl and RV, but not for nuvi 2797. The reason the US 2797 isn't offered BC20 as an accessory escapes me at present, but i'm suspecting only a marketing ploy by Garmin.

dezl760, nuvi2797/2798[US] and RV760 all have the same PCB P/N of 105-01878-02, and while the 2 nuvis use the same firmware, it's different to the dezl and RV firmwares and the 3 have different HWIDs. They should be fully cross-flashable but a safe way to experiment would be to try initially using the original unit's HWID and boot.bin.

I would be interested to see if 2797 can work in the RV/dezl/2798 reversing camera mount. Although 2797's not listed as being compatible with the BC20 reversing camera that doesn't mean it isn't of course. Garmin may simply want ppl to buy a dezl, RV or the US 2978 which has DC20 included. As the US 2797 and 2798 share the same fw and hwid i'm betting that 2797 can in fact use the wireless mount and the BC20 [there is an EU model 2798 but it's not the same as US 2798, it has no back up camera, the '8' simply indicating that its supplied with a HD/FM GTM70 Traffic Receiver whereas the EU 2797 has only an FM model in the box]. The only thing which may limit that compatibility of the various US units would be if there are different pinouts in the unit to mount connections of 2797 compared to 2798/dezl/RV or the 2797 has some hardware disablement on the board.

If you are wanting to experiment johotx, i'd be happy to assist with making firmware packs for you to try various conversions and i'm sure Loly would do so too. Just say what you want to try, dezl > nuvi and dezl > RV both, or just one. Be all at your own risk of course, but should be totally safe. If i had any of those units and a BC20 i'd try all combinations myself without hesitation.