ST-Link v2 clone

Popular cheap ST-Link v2 clone from China

STM32F101CBT6 is used instead of STM32F103CBT6 that may be found on "regular" ST-Link v2. Fun fact: STM32F101CBT6 does not officially has USB device.
See also: https://github.com/blacksphere/blackmagic/issues/62

Board markings MX-LINK V2 2016-01-18.

ST-LINK recognizes it as firmware version V2J21S4 and shows serial number.

I have also slightly older ST-Link clone with different pinout:

This one has only single LED. Again, STM32F101CBT6

There are four PCB points for manufacturing purposes, in order: SWD, GND, SWCLK, +3.3V.

There was no isolating foam on the "bottom" side like in newer version - I would recommending adding one to avoid short to aluminum case and/or between PCB pads.

ST-LINK Utility recognizes it as "Old ST-LINK firmware/ST-LINK already used" (no serial number?), firmware version V2J17S4.