Well, i tried plugging it in second time with the same result, but then I thought "three times a charm" and did it once again. Somehow it worked. Thank you very much!
It was indeed problem with my flash drive. It was formatted correctly, but for some reason it was deleting all data from ps3 folder everytime I was unplugging it from my pc (I don't understand why, but that doesn't matter I guess). I used another one, and finally I see some other message, this...
Sorry for writing here (and my bad english), but I don't know where should I ask. I was trying to bypass the update with given file, but I accidentally updated to 4.90. Right now when i switch on my console it stays on for a few seconds, then turning off and the message about updating to 4.90 or...