Incidentally, your "easiest" way to utilize an 1142 might be to get a x800 and put 8.3 "Mobility Express" on it, or even just put autonomous firmware directly on it if you only have one. Or just huck it into the trash, unless something about it means it needs to be kept around.

https://software.cisco.com/download/home/286304960/type/286289839/release/8.3.150.0

https://www.amazon.com/Certified-Refurbished-Cisco-AIR-AP2802I-B-K9-802-11ac/dp/B07FK1PSW8

Autonomous firmware may be called c1140-k9w7-tar.124-21a.JY.tar but that's all I can tell you about that <whistles while walking away from that topic>