You cannot brick a Thunderbolt!!!! If you can, then I bricked mine almost 10x's...I was stuck at the HTC screen forever...What I did???? Someone told me to hold down the vol key and power key to get back to clockwork...Didn't work...instead it brought me back to the step 6 process of manually rooting the Thunderbolt...from there I did step 7 again:
Push SU, busybox, and psneuter.
adb push psneuter /data/local/
adb push busybox /data/local/
adb push su /data/local/
adb shell chmod 777 /data/local/psneuter
adb shell chmod 777 /data/local/busybox
To gain root:
adb shell
/data/local/psneuter
The following will remount /system and set up SU:
adb shell
mount -o remount,rw -t ext3 /dev/block/mmcblk0p25 /system
/data/local/busybox cp /data/local/su /system/xbin/su
chown 0:0 /system/xbin/su
chmod 6755 /system/xbin/su
Now i'm rooted after bricking my device...i found it on accident but if you ever panic just try it out
Push SU, busybox, and psneuter.
adb push psneuter /data/local/
adb push busybox /data/local/
adb push su /data/local/
adb shell chmod 777 /data/local/psneuter
adb shell chmod 777 /data/local/busybox
To gain root:
adb shell
/data/local/psneuter
The following will remount /system and set up SU:
adb shell
mount -o remount,rw -t ext3 /dev/block/mmcblk0p25 /system
/data/local/busybox cp /data/local/su /system/xbin/su
chown 0:0 /system/xbin/su
chmod 6755 /system/xbin/su
Now i'm rooted after bricking my device...i found it on accident but if you ever panic just try it out