Unable to install bootloader on MotoDroid with froyo FRG83D I'm attempting to root my phone and have placed an update.zip in the root of my SDCard.  I get the message that the zip is not signed and the update fails.

I understand that VZN started added this checksum to make sure that only official OTA's can get installed.  Does anyone know howto get past this so that I can root my phone, so that I can install cyanogenMod, so that I can do wifi hotspot tethering?
You may have a bad file, either from a bad source or it just got corrupted.  I would try again.  Follow this tutorial on DroidForums.net.  It reportedly works fine with FRG83D.