JavaScript (ES6), 25 bytes

-1 thanks to @thejonymyster

-7 thanks to @Arnauld

x=>x.replace(/pl|1/,z=>+z?'pl':1)

Swaps the first instance of -1 and 1, saving 1 byte when the program compresses itself. Takes the list of bytes as input, as a string.

This is quite the community effort now :p