my handset is sim locked o2 i have no problem with that, i want to reflash the firmware/os to the standard RIM os/firmware as if it was shipped from the factory sim free as standard?
If you are talking about the branding of your Blackberry it's not related to the sim lock and the OS can be upgraded but carriers release the OS, you can use some OS from another carrier if you would like to change the one that installed on your device.
To unlock your Blackberry you only need to use a unique unlock code, it will make your Blackberry work with other sim cards and not only with O2 sim cards (when the sim lock is active your Blackberry will be able to connect to the network with sim cards from the original carrier only).
About the OS, well you always can change the OS to another OS release.. you only need to delete the vendor.xml files from your computer.
By the way, changing the OS won't effect the SIM lock. it will stay unlocked or locked even if you will wipe your Blackberry.
If you are trying to get rid of the O2 splash screen that appears when you reboot the phone, you can't. That is hard-coded into the device and can't be changed, even by installing a different OS.
