if you're experiencing the red triangle horror, don't be afraid it's quite common.
This triangle shows up when you try to reboot in recovery mod but the recovery image couldn't be loaded.
The easiest way is to use ROM Manager to update your recovery to the latest available and then press "reboot in recovery".
Otherwise, you can try to flash recovery image by hand.
Download the latest recovery image  and follow the method listed there which is :
adb reboot bootloader
fastboot flash recovery recovery-clockwork-22.214.171.124-legend.img
EDIT: of course these two commands are to be executed in a shell command when your Legend is connected to your computer and the image file is in the current directory, otherwise put its path.
1: from http://forum.xda-developers.com/show....php?t=1290841