How to convert HEX2 to RGBA?
JavaScript (ES6), 73 54 50 bytes
(Saved some bytes thanks to @LeakyNun, the edited challenge, and @CraigAyre.)
s=&gt;s.match(/../g).map((c,i)=&gt;('0x'+c)/(i-3?1:255))



let f=

s=&gt;s.match(/../g).map((c,i)=&gt;('0x'+c)/(i-3?1:255))

console.log(f('00ff0080'));