We want to replace the 49" TCL with a 50" Samsung Smart TV. I thought it would be easy. The four fasteners that hold the bracket to the two elevator arms look to be Torx. I have a complete set of Torx drivers. T15 is too small, T20 wants to grab but spins in the fastener, T25 is too big.

Did Grand Design use something weird that looks like Torx but isn't? What have others done to remove these? Any tricks would be appreciated.