This link is for the DROID X and it will update your to baseband .13P, which is the baseband used by the newest leak from moto (not yet released).
I would like to thank and give credit to Framework43 for providing me with the ingredients. Please follow him at twitter.com/framework43 for updates on MIUI releases for the Droid X.
Instructions: Flash the zip from clockwork recovery just like you would any rom. No need to wipe anything.
Hey DXC, will this fix the issue with the Droid X losing service randomly and requiring a reboot to get it back on MIUI? Thanks for asking, but unfortunately we won't know until we try it. Some people reported that the .12P fixed this issue for them, while others say it did not. Maybe they'll have more success with .13P, but I want to point out that this is not just a Miui issue, it is an issue that has been reported on CM7 and Liquid roms as well, so it seems that it is affecting all 2nd-init roms.