While I've left in most of the I/O in case some mad scientist decides to turn the joystick ports into a Datasette or IEC interface, I don't think the RS-232 routines are worth keeping around. The Commodore 64's built-in RS-232 code could barely keep up with 1200 baud.
this copy of atari64.xex was compiled with the HELPRESET flag, so you can use the HELP key as a RESET key, until I figure out how to trap that key properly in a RAM OS. The roms are compiled without this option. This process isn't automatic in the build script.