Hi,
RV roofs are generally made of either TPO or EPDM and are sealer specific. Using the wrong sealer on the wrong material can be big trouble.
To find out what material is on your RV's roof:
Locate a roof vent, like the one in most bathrooms and remove the trim ring, 4 screws.
Look at the roof material stapled to the inside of the framed opening.
If one side is white or dove color and the other side is black, it's likely EPDM. Use DICOR products to repair/seal. If the material is all one color, it's likely TPO. Use Alpha Systems products to seal/repair. The DICOR or Alpha Systems products are what are used at the factory during manufacture.
For my RV roof I use "DICOR self leveling sealer" in a caulking gun. For any cracks (or suspected problem locations) in the existing sealer, gently remove any spots that have already separated. If there is no separation of the existing failed sealer, its OK to leave it and cover with new sealer. Clean the spot with Fantastic, then rinse with a damp cloth. After it dries squirt on the sealer from the caulk gun and let dry. It will self level.
As for Eterna bond tape, I would NEVER use it on any RV I was planning to keep. To properly use the tape you have to seal all edges/seams of the tape with sealer anyway or else the edges will eventually curl and allow water in. Also, if you ever have to remove the tape for any reason, roof membrane damage will result.
Lee