Where to download official upgrade?
Android™ 2.2 (Froyo) software update for DROID X by Motorola. The software update (Motorola Version.2.3.15.MB810.Verizon.en.US/BP_C_01.09.07P)
I don't believe that this is doable. I doubt if the SD card can hold an entire operating system. It's like trying to put a quarter into a dime slot. However, try going to either the Google site or the Motorola site and looking for the upgraded OS and try downloading it. I know that the Motorola site has it.
I cannot find on GOOGLE site and on MOTOROLA site
I have found only here.
But it not official upgrade.
Update is only about 63mb.
Why would you not let the phone do it it's self? You press the far left hard key on the homescreen, then press the "Settings" softkey, then scroll all the way to the bottom and press "About phone" and from there at the very top press "System updates" and do what it tells you to do.