Or just don't support it. Most phones running 1.5 are underpowered, and if users haven't upgraded they probably don't care about being on the cutting edge and aren't buying many apps. I'd expect that the effort isn't worth it unless you have huge sales volume.
Sprint's Hero got 2.1 through an over-the-wire update and GSM Heros have gotten updates in other countries. Scream at your carrier if they don't have similar.
