I do this..
"1. Download
PB31IMG.zip and place it in the root of you SDCARD. Make sure the FS is FAT32, otherwise PB13IMG.zip will not flash.
1a. Link has been updated so you no longer have to apply the VZW exchange OTA.
2. Now go to the bootloader.
2a. Run 'adb reboot oem-42' if powered up or hold Power + Volume Down if your phone is off.
3. It should automatically start loading PB31IMG.zip. Then accept it when it asks you to load it or not (pretty sure Vol Up).
4. You are now completely stock. You should remove PB31IMG from your SDCARD now.
5. Download
dinc_ota.zip, rename it to update.zip and place it in the root of your SDCARD.
6. Now boot into recovery and apply the zip.
6a. adb reboot recovery if powered up or Power + Volume Down then select Recovery.
6b. Now hit Power + Volume Up to bring up the Recovery menu.
6c. Now select apply update.zip
7. Go to Settings > About phone > Software information > Baseband version and verify that it's 2.05.00.06.11.
8. Now download and run
Unrevoked 3 to reroot and install ClockworkMod recovery.
9. Now you can go ahead and do a Full Wipe then install the Stock Froyo rom."
At the part where I put the file to apply update I am back at that black screen.
I am following the directions.