Hello eroselim,
Yes you can.
My l620 is from russia (cv eu ru) and I follow 10 days ago
this tutorial. My l620 changed product code after that and have full functionality - MAKE SURE YOUR PHONE IS SIMFREE before trying that.
JFYI: NSU for retail will go crazy after you do that cause hardware product code don't match software product code.
Then yesterday I saw that amber update is available to download through NCS and I did it all over again but back to original product code. Try similar steps in NCS to download firmware for RM-846 but you must know exactly product code you are after. :sweaty:
Good Luck!
p.s.-Your phone will be full wiped after process except sim card and sd card.