Problem (probably) solved.
I needed bigger array for RCPT mails. And when I change size of those array from 36 to 45 bytes, I remove dummy array and it work without it
Then I just change in serin2 to receive 45 bytes and everything work well.
I always leave 1 byte longer array, and set last byte to 0...
I'm not sure what last 3 array have with pass array...