Just to let you know this does not work on all Xoom models like you say.
unfortunately, I can confirm this. I restored my xoom to stock 3.2 and tried to root using this method, it gets stuck at the afore mentioned step. (uploading xyz succeeds, running "xyz stage1" stops working at some point)
Not this method. It is supposed to unlock and root motorola devices in 10 minutes without deleting any files.
I'm sorry if what I said was not clear enough. I was talking about unlocking the bootloader which is the first step in rooting the classic xooms and DOES wipe everything (/data).
This method on the other hand does NOT unlock your xooms, though. This is "just" rooting your tablets (and installing busybox) but it will not unlock your bootloader. Therefore, this method will not wipe your data (at least not intentionally)