Exploit to unlock Motorola bootloaders
The bad news is, this only works for Motorola devices on Qualcomm platforms. Nevertheless, I'm posting it here in case it becomes useful: http://blog.azimuthsecurity.com/2013/04/unlocking-motorola-bootloader.html
I heard there are also exploits for the omap3 Motorola devices that have signed kernels. Thanks for the link.
I don't think that's the case. http://forum.xda-developers.com/showthread.php?t=1443678 is a long thread on unlocking the omap3 Motorola Defy, and just by skimming it you can tell it was eventually found to be impossible. If its bootloader weren't locked, the Defy might be a good target for Replicant (I know it's already evaluated as "impossible" in TargetsEvaluation). Motorola may support it with their unlock program, but look these terms I found in their agreement:
"User agrees not to transfer (i.e. sell, lease, or otherwise receive compensation from any third party for the right to use, possess, or operate such Device) such Device to any third party..."
"User authorizes Motorola to disable the Device and/or its connection to a wireless network, or to authorize a Wireless Carrier to disable the Device and/or its connection to a wireless network...in Motorola's sole determination..."
This takes away all the freedom the user gains from installing Replicant.