Do not use ROMs from random file-sharing sites. Stick to XDA threads from 2016–2020.
The MZ604 was a legendary device for one specific reason: it was the first tablet to be granted an official unlock method from the manufacturer. But "official" in 2011 meant "voiding your warranty and praying you didn't brick it."
Elias connected the mini-USB cable—the fat one, not the micro that came later—and fired up the Android Debug Bridge (ADB) on his Linux terminal. motorola xoom mz604 custom rom
adb reboot bootloader
The screen went black, then displayed a stark warning text in the center. This was the "locked" state. To flash a custom ROM, Elias needed to unlock the bootloader. Archive
"It’s funny," Elias narrated. "Back in the day, unlocking this voided your warranty instantly. Now, nobody cares. But the process is risky. One wrong command, and this becomes a paperweight."
He executed the command:
fastboot oem unlock Do not use ROMs from random file-sharing sites
A terrifying prompt appeared on the Xoom. THIS OPERATION WILL VOID YOUR WARRANTY AND ERASE ALL USER DATA.
Elias confirmed. The tablet rebooted, wiping itself clean. When it returned to the bootloader, the "Lock State" read: UNLOCKED.
"First hurdle cleared," Elias grinned. "Now we have to fix the software."
Note: Unlocking may wipe data and void warranty.