Booting into fastboot with a normal cable still showed the error message but instead of "launching RSD mode 2" it said "Starting fastboot protocol support". However, fastboot on my PC couldn't see the Xoom. The factory cable fixed this.
dude you are the MAN!
I had really bricked my UK WiFi Xoom - it would instatly come up with loading RSD and a LNX 000x2 error - adb couldnt see it, fastboot couldnt see it, I plugged in my cable and "der duh" - it was recognised. I rebooted using the P-up method, clicked down and got into fast boot thingy where I was able to re-enable unlock, and flash teh motorola image form the website
i'm not use Mini-to-Micro usb (i don't find it in indonesia),i just use standart micro usb.if you don't find Mini-to-Micro USB adapter cable (SKN6252) you can use standart micro usb.there is 5 pin and 4 cable (red-green-black-white),just connect red cable with none pin (there is 1 pin not use/not connect with any cable),use another cable to connect it with solder.
i'm sorry my english bad,haha..but i'm glad if everybody solved with this problem.
I don't know about Motorola mini to micro usb,because i'm not use that cable.I use stand art micro usb (just like in the picture).and just only 4 cable,not 5.no cable brown,you can make your own cable like me,its work.first my pc not recognise the device,but I try another usb port,and viola...my pc recognise n install the usb driver automatic,and then just run 'fastboot oem unlock'.
Note : if your cable work,your screen XOOM must be on when you plug in your cable to your pc,and must be off when you unplug your cable.