k800i red52 unlock and upgrade to red53

Hi,

I'm currently running a patched (unlocked with setool) r8ba024 red52 firmware (Dutch). I would like to put the latest dutch firmware in there, but the only one that is available is one with red53. I would like to upgrade and I don't mind loosing its modding potential.

What is the procedure that I should follow to upgrade to red53, officially unlock and to have the latest red53 firmware? Should I use D-Ultimate Unlocker before or after the firmware upgrade?

Thanks!