Fake PL2303

Preface

I'm pretty confident that most of us electronics hobbyist own (or at least know) one of these cheap no-name USB-to-Serial adapter. It is very cheap, comes with pin headers output, and it works kinda ok, until one day it just stopped working. This guide is hopefully what you need to fix this issue.

Symptoms

The most common issue with these blue plastic adapters is that it just stopped working for no reason at all. Maybe you just updated to Windows 11 or installed something from Windows Update and now it will not show up as a serial port on your computer.

Checking in Device Manager and you will see one of these error messages on your adapter:

• THIS IS NOT PROLIFIC PL2303. PLEASE CONTACT YOUR SUPPLIER.
• PL2303xxx DO NOT SUPPORT WINDOWS 11 OR LATER, PLEASE CONTACT YOUR SUPPLIER.
• PL2303HXA PHASED OUT SINCE 2012. PLEASE CONTACT YOUR SUPPLIER.

The Cause

If you got the first error message, this means your PL2303 chip is fake. Fake PL2303HXA/HXD chips are very common on these Chinese devices. Just like FTDI, Prolific decided that enough is enough and disabled all the fake devices from using their driver.

Prolific also ended support for many chip variants (HXA/TA/TB/HXD/RA/SA/EA) at Windows 10. Therefore, even if you have a real chip, it will not work on Windows 11. This is pretty frustrating because end users probably don't know which chips are used in consumer products and have no easy way to repair them, but I'm not in a position to comment on this.

The Fix

To fix this issue, you need to buy a new chip. Prolific recommended a PL2303GC as a drop-in replacement that works on Windows 11. You can buy this chip from LCSC. This chip usually costs around 2$ each. Maybe more expensive than your adapter lol.

I cracked open my adapter (luckily they did not glued the case shut) and see this SSOP-28 chip with no markings on it. It took less than 10 minutes to use a rework station to pull the fake chip out and put a genuine one in.

Now I put the board back into the plastic case, and plugged it into my computer. Looks like it works fine now. I'm glad that at least Prolific provides a new drop-in replacement. Thanks for reading to the end!