Rooted 1.5 to 2.1?

[mnxd9]

Sorry my head is spinning I just can't seem to find a good answer anywhere, phone is on 1.5 rooted time to go up to 2.1 is there a good guide for this? I find plenty of guides for rooting 2.1, that all assuming you already have 2.1, I'm leery about just upgrading OTA through sprint and messing something up. Then I assume sprint is will give me the .6 version then I'd have to downgrade to the .5, I would think there is an easier way. Little green on Andriod, I rooted it, but that was sometime ago, never did anything more from that point.