Re-gaining Root Access after Cupcake Install

The Official HTC website has been updated to offer instructions on how users can flash their Android Dev Phones with a factory Android platform system image and associated radio images.

With these system image files, Android dev phone users can:

Keep their Dev Phone up to date with the latest Android system images Test their application on multiple Android platform versions, to ensure compatibility
Restore a corrupted device to a factory state The Android 1.5 radio image, system image, and recovery image can all be downloaded here

After doing this I LOST root access, but I have found out that people easiest way to re-gaining root access. Follow These Steps :

adb shell
su
mount -o remount,rw -t yaffs2 /dev/block/mtdblock3 /system
cd /system/bin
cat sh > su
chmod 4755 su

*reboot*