Before you proceed any further please check out this blog post i created on installing and downloading of Nokia and Lumia phones Firmwares Here.
Most of the download links are not in english, you can use a browser with authomatic translation i recommend google chrome browser.
Downloading and Flashing a Firmware can help you to reset and recover your phone software at anywhere and anytime without a need for an internet connection.This can really help you if your phone is not responding, frozen, experiencing software related or software update problems.
You can also request for more Lumia 620 firmwares with product codes by commenting on this post.
Model:Nokia Lumia 620 (RM-846)
Title:VAR EU-UKRAINE UA RU CV
Country: Ukraine (Multilanguage change in settings)
TOTAL SIZE ABOUT 534.9MB
Model: Lumia 620 (RM-846)
Name: VAR EU CV RU
Country: Russian (Multilanguage change in settings)
TOTAL SIZE ABOUT 661.1MB