Hi, I just want to share experience with STLINK/V1 reapir. If you fry your STLINK, there is a possibility to get it repaired. One way to do it is to replace the chip by another one, by cannibalizing a discovery board. But wait, there is a catch. STLINK V1 and V2 differs in hardware. Luckily, not much. There is some work to be done, so one can use STLINK V2 firmware for STLINK V1 hardware. Today, I have repaired old STLINK V1 and I'd like to share my experience with you:
After removing the chip and soldering the good one, you might want to download a code to it. The unpopulated conector near the MCU has all pins needed for that. You don't need to solder wires to the tiny fine legs. If you have already soldered pre-loaded (cannibalized) chip, just follow the next steps:
STLINKV2 has got some resistor for version (or something) identification. These resitors (there are actually two) weren't used on STLINK1. You must solder one resitor, 10K from pin 2 (PC13) to ground. Without this resistor, it absolutely denies to work.
Nex, you must add 100ohm resistor between pin 25 (PB12) and 27 (PB14). STLINKV1 hasn't got any. Without this resistor, it also does not work. It looks like, without this resistor (PB12 left open) it fails to read data from SWDIO line. SWDIO just does not switch to input state and the two pins (STLINK and target MCU) begin fight. Fortunately, there is a protection resistor soldered on STLINK, so nothing will make smoke (I hope).
Third difference is the RESET pin connection. On STLINKV1, reset pin was 19 (PB1). STLINK V2 has reset on pin 18 (PB0). Don't forget that, otherwise "connect under reset" will not work. There is an easy solution, no need to peel and wire any traces on the PCB - just use pin 3 (TRST) instead of 15 (RESET) on the 20pin header connector.
Note: If you repair a board, which has failed by overvoltage, please check and measure ALL protection circuitry near the 20pin header connector, though the parts (especially) resistors don't look fucked, they might be open. I had to change four of them, only one was visibly charred.
Have a nice day, I hope, it will help someone someday, bcs I've lost half a day on this sucker
One photo of the botch repair: