ground attack suite from A-10 and electronic defenses from A-10.
So, essentially no upgrade what-so-ever.
A-10A or A-10C? Baseline A-10 of course had only Mark 1 Mod 0 eyeball, but even that soon got Pave Penny and INS as an upgrade; arriving at current-block C model it has LASTE, GPS, support for targeting & navigation pods, helmet-mounted sights, and night vision goggles, digital stores management, etc. Of course, neither version has onboard internal radar, RWR, or ECM if that's what you meant...

But then again, quick browsing through sourcebooks tells that most Hunters only had a basic ranging radar without any specific air-to ground avionics even in FGA.9 version, only the Swiss decided to later upgrade their Hunters with chaff/flare dispensers, RWR, and Saab-made bombsight.