[EVO 4G Android Development] frankenstein\:
OK, to answer this question... This method might work if you still have root access under unrevoked.

It will work for those that did the real full root process using toasts part 1 and part 2.

Unrevoked is a hack that allowed su access but didn't fully unlock the phone. The hack they used was patched by the OTA release which would kill your ability to do what's necessary to execute part 2 of toasts process.

The key will be if you can get the mtd-eng.img image to flash to the misc partition there by resetting the mainver of the device.

In order for this to work you must have root access so you can cat (copy) the flash_image file to the /data directory. It is the only directory you can copy the file to that will allow you to execute it once you chmod 755 the file.

The sdcard is mounted such that nothing can be executed from it. You can read and write there but not execute files from /sdcard regardless of what permissions (chmod) you apply to a file there.

I've tried to apply this OTA via calkulin's method and via whitslack's method as outlined on the board here, each with the same result. Once applied, 4G scans but never finds or connects to the network.

My root and nand unlock was maintained through both attempts. In both instances, when you adb shell into the device your presented with a $ prompt instead of the root # prompt. You must enter "su" at the $ prompt with the phone turned on so you can approve the superuser access request on the phone before being able to get to the # prompt. Once you do so you should be able to su the adb shell $ prompt from the on without being prompted again.

I rooted via toast's part 1 & part 2 processes and was able to recover by doing the following:

1. flash the mtd-eng.img from toasts part 2 to reset the mainver. Follow the instructions in part 2 for this.

2. copy the part 2 pc36img.zip file to the root of the sdcard

3. power off the phone, then hold the volume down key and power it on, let it find and scan the pc36img.zip file, when asked if you want to flash it select yes and then yes again to reboot when the flash is done.

4. re flash your recovery using the same method used to flash mtd-eng.img. i.e. flash_image copied to \data via cat command, chmod 755 it, then \data\flash_image recovery recovery.img (sub what your recovery's image file is named) I use RA's 1.7.0.1 recovery.

5. reboot into recovery and apply the evo.1.39.00.05.31.zip radio image via the flash zip file method and reboot.

6. boot into recovery and restore the nandroid backup I did just before applying the ota patch for the first time.

At this point I am back to where I started with full 4G functionality. For me, this was rooted via toast's part 1 and part 2 processes and running Flipz rooted .6 stock rom which I have removed a good deal of bloatware from and added things like wifi tether and root exploerer among other things of use...

I've done this twice, once following calk's update method and once following whit's method and both times the above process has restored my 4G functionality.

I can't guarentee this will work for unrevoked but I'm fairly sure that if you can get a su shell going you should be able to do this. Again, the keys are the ability to cat (copy) the flash_image file to the /data directory, the ability to flash the mtd-eng.img to reset the mainver and the ability to flash a custom recovery in order to be able to apply the raido image.