Hey everyone,
After I did the radio update (after doing the full root) my 4g was really messed up. The 4g would just not stay on and kept going out and then coming back every few secs. I tried reflashing the radio and yes I also formatted the cache right after and going back to the old radio. Then I tired going back to stock and it was fixed
but when I did the full root again without the radio update after, well the 4g was back to crap. I even tried a custom rom after the root and still no go. So after doing many tests I found out that the firmware for the wifi is different from stock and full root. I found this out by going to ##DEBUG# then WiMAX Engineering...The full root had 20100401 (im guessing its the date of the firmware) and the stock had 20100423. So after more testing this is what worked for me.
1. I took the image file from the first part of the root (PC36IMG.zip)
2. Then I extracted android-info.txt and wimax_25043_R04.img
3. After that I made a new zip file with those two file from above and named the zip "PC36IMG" (without the quotes).
4. Then I put the PC36IMG.zip on the root of the SD card of the evo.
5. Then I booted up to the bootloader (u know the screen with the androids skating). Then I did the update and reboot.
After that my 4g was working without getting droped every 5 secs
If someone else tries this please let me know so I know that I didn't just get lucky.
P.S. IM NOT RESPONSIBLE IF ANYTHING BAD HAPPENS (it shouldn't but hey shit happens lol)
I also posted this on xda...
Enjoy your 4G back!