Problems downgrading an unlocked Storm 2

I'll try and make this brief.

I have a Storm 2 ( originally on o2 network , unlocked so I can use my Vodafone SIM )

Updated firmware to 5.0.0.713, want to downgrade to another OS. I've tried everything, uninstalling the earlier OS from the PC and reinstalling, deleting vendor.xml.

DM v 6.0.1.18 shows the installed BlackBerry Device software 5.0.0.607 but when I ask to update the OS it says none available. Application loader shows no update either.

I've attached the Storm 2 ( 9520 ) to another PC running Win XP and used DM version 4.6. OS installed on the PC is 5.0.0.607 . DM says it's there but asking to update my device doesnt. Ive wiped the device using JL_Cmdr but all I can do is restore the device back to 5.0.0.713.

Is it possible the firmware 5.0.0.713 is locked someway to prevent me reverting back to earlier OS ? the 5.0.0.607 I've downloaded is not a leaked firmware but an official one. Any help or advice would be much appreciated. I've exhausted just about every "downgrade" post and forum I can find.

First I will assume that you already searched the tutorials for upgrading/downgrading your OS here in CB

Did you make sure that you deleted every trace of previous software from the computer you were using?

(computer> C drive> Program files> common files> Research in motion> shared - then delete loader files)

*also delete from: control panel> programs and features - then delete any bb OS file listed

wipe your phone with JL_Cmdr (or BBSAK - my preferred choice)

once this is done - install the .607 OS to the computer (and delete vendor.xml) then load to your phone

I agree with ray's suggestions.

there should be no need to wipe the device, but you do need to make sure you do the downgrade VERY carefully.

first step would be to uninstall EVERYTHING blackberry from your computer - desktop software and any device software installations. go through the control panel, add/remove software. then, navigate to "\Program Files\Common Files\Research In Motion" (if its still there) and delete any residual folders and files that may have lingered there during the uninstall process.

next step is to re-install everything to the computer. start with desktop software, then run the os installation package for the device in question and the version you want to have loaded. once that installation finishes, navigate to "\Program Files\Common Files\Research In Motion\AppLoader" and delete the vendor.xml file.

with the "\Program Files\Common Files\Research In Motion\AppLoader" folder still open, double click the "Loader.exe" file to begin the application load process. follow the prompts to complete the installation. if you are asked to downgrade the device software, click yes.

I've thoroughly exhausted all the downgrading tutorials but I'm happy go with everyones suggestions just to be sure.

As stated though, I have tried this on another PC with a clean build of XP - same results.

Interestingly I tried downgrading my works BlackBerry today and had no problems so I know I'm using the correct method. I still think it's something with the handset OR the OS I've downloaded.

Have you tried the APP Loader method with the battery pull trick???? that should work np but backup your device prior...