i snagged this from the Damage Control ROM thread at XDA and it fixed my 4g nicely. I didn't use ADB to do it -- i just used root explorer (you can use whatever file explorer app you want i guess) to move the file instead of renaming it.
If you are stuck scanning:
go into
adb shell
ls /data/misc/wimax/
look for a file with your macaddress ending in .tree.xml. we want to move that to another location so it gets regenerated.
mv /data/misc/wimax/macaddress.tree.xml /data/misc/wimax/macaddress.tree.xml.orig
add:
i am using this radio right now. i flashed it and it's the only one that has ever worked for me. it seems to hold a 4g signal better now, too.
xda-developers - View Single Post - [Radio & WiMax] 2.05.00.06.10 update.zip (Full IMG)