The Prolific 2303 is a USB to serial controller. Cloned versions of the controller was commonly found in serial adapters from Ebay/China until around 2014 when Prolific began bricking cloned devices by overwriting the firmware via the drivers. Since then, most cheap serial adapters on Ebay use the CH340 or CP2102 controllers instead.

The driver detects a counterfeit device is by exploiting the behavior of a real chip where write requests to an even address are deferred until it receives the next subsequent request at the odd address. If this address is not subsequent to the even address, the write is request is ignored. Clone chips perform each write immediately which allows Prolific's driver to overwrite the firmware.

Troubleshooting[edit | edit source]

THIS IS NOT PROLIFIC PL2303 PLEASE CONTACT YOUR SUPPLIER[edit | edit source]

Prolific's newer drivers will check whether the Prolific chip is authentic and if a clone is detected, the driver will refuse to function. Windows will automatically download the latest driver which comes with this 'feature'. Fortunately, their drivers no longer brick the counterfeit device. Short of buying another serial device, the only way to get around it is to use an older version of the driver.

There is a copy of version 3.3.2.105 of the drivers compatible with Vista in the Cloud/programs/drivers directory. This driver appears to work with Windows 10, though a BSOD can be triggered if you attempt to share/unshare the device with VMware.

Alternatively, download the .exe installer and run it inside a VM and then navigate to AppData/temp and retrieve the .inf and .sys drivers from there.

See Also[edit | edit source]