I've just started using Chirp with a Baofeng UV-5R and a USB serial adapter that Amazon claims is from Baofeng. The adapter has a genuine Prolific chip (or a darn good counterfeit), and Windows 7 Pro 64-bit recognizes it as a serial port; in addition, I can connect TxD to RxD at the radio plugs, open PuTTY, and see looped-back characters I have typed on the console. So far, so great.
However, neither Chirp nor baoclone could open the serial port the USB adapter was assigned to: COM19. Hmmm, 19? Sounds way high for a serial port enumeration. I reassigned the USB adapter to the vacant COM2, and hey presto! Both utilities are able to talk to the radio.
Sooo, beware of high-numbered COM ports.
Incidentally, is it normal for the UV-5R to key up when the serial cable is present? I'm going to make a practice of always having a dummy load connected when programming this radio.
Regards, Steve