[Q] Lumia 1020 newbie. Flashing question topic

Hello,
just got my Nokia Lumia 1020, have bought it on eBay and unfortunately it has Telekom branding. Can I update firmware to get this branding away.
it is not sim locked, just branded.

I have no idea at the moment about WP firmware updates and upgrades, but have already found what my phone isЮ
059T7B2 RM-875 VAR EU DE TELEKOM WHITE

Which newest firmware should I take and where can i get it(didn't found it here).
And is there firmware update tutorial?

Sorry for such a newbie questions, but It is my first WP8 phone.

Thank you in advance!