Rad hardened is only for GEO or long term missions. If you're throwing cube sats, or other micro (maybe even a small) sats, you're going to use off the shelf hardware. If you're worried, throw a little polyethylene around it. First few mm are going to do the majority of shielding. But at these low altitudes you're not going to get many bit flips and semiconductor damage isn't a concern because the low lifespan of the satellite. For the little errors you get, you can always reupload software, which you check on large or small satellites.