I’m pretty sure they never integrated HARM onto the Mig29. Instead they rigged up a special tablet computer to allow communication with and launch of the missile using a special pylon.
At 0:58s of this video, you can just make out the top of the tablet at the bottom left of the frame.
In theory, so long as the pylon is compatible with the AMRAAM missile, they should be able to do the same using a software update to the tablet.
The biggest issue will be down to the practicality of how much manual input is required on the tablet, which in turn depends on how advanced the software is.
If the pilot needs to manually key in GPS coordinates on the tablet, that’s obviously a massive PITA, but is at least theoretically possible against a deployed SAM site as they are not going to be going anywhere in the 30-60s the pilot might need to key in the coordinates. But that is not going to work against fast moving air targets.
If the tablet can wirelessly pair with the commercial GPS satnav units also shown in the above video, and can display a moving map of live location of the Mig29 and allow the pilot to using touch input on the map to feed coordinates to the missile, then that might work against a completely unawares opponent by having the pilot guesstimate where the bogey will be, factoring missile flight time (XX seconds), and try to put the missile within seeker range of where the bogey will be in XX seconds. It can increase its odds by volley firing multiple AMRAAMs at different locations to maximise chances of one missile getting within range.
Massively suboptimal, but at least workable in theory. It also does away with mid course updates so the Mig can shoot and scoot immediately. It will have very low KP, but should also minimise the risk to the Mig, so if it lives long enough to keep taking pot shots, eventually it will get lucky.
Obviously they won’t be hunting Flankers like this (well, at least they shouldn’t), but they might catch some Su25s out, especially if the Su25s are making multiple passes against fixed ground targets.