Arduino for STM32

Try to exchange Rx and Tx pins.

Did that as well, out of curiosity... No change, unfortunately.

retry again when you received your st-link (note swd)
in the mean time you may like to order different boards, robotdyn (given earlier) has the 'stm32f1 pill' equivalent boards, i think various boards have the same pinouts as the blue pill.
a nucleo has an on board st-link hard wired

Thanks, I will do that. I contacted the vendor for an explanation - we will see how they react. Is it possible to tell fake boards from the chip? Mine look like this:

dab a paper towel in little water and 'clean' the chip surface, it looks like the markings may be erasable.
i think 'proper' chips markings are laser engraved, that won't be 'erased' simply 'cleaning' with a paper towel

but the best test is actually what you have already done, after you set boot0 and press reset
the stm32 is in uart upload mode, i.e. it should respond to commands with ACK or NACK on the uart
if it doesn't do that it tells a lot about the chip in question
https://www.st.com/resource/en/applicat ... ronics.pdf

if you get the boards e.g. from robotdyn and those works, you may have a stronger case against the vendor
olimex i think is bulgarian and they make rather good boards has rather good documentation about their boards
they have a forum as well and provide support
but do note that their 'duino' 'uno' style board uses micro 10 pin adaptor for the jtag/swd connector.
https://www.olimex.com/Products/Duino/S ... e-hardware
they stock an adapter for it as well
https://www.olimex.com/Products/ARM/JTAG/
https://www.olimex.com/Products/ARM/JTA ... TAG-20-10/
nevertheless you can still program it over uart at PA9, PA10

I used both water and acetone and after both "treatments" the writing withstands.

you do upload from IDE? what are your Tools menu settings?

Juraj wrote: ↑Wed Jul 15, 2020 9:39 am you do upload from IDE? what are your Tools menu settings?

No, not yet. I am just using ST Cube Programmer at the moment, as I had the first error messages in the Arduino IDE (with the most recent core installed etc.) and then tried to reduce the impacts of other software.

Miq19 wrote: ↑Wed Jul 15, 2020 9:52 am

Juraj wrote: ↑Wed Jul 15, 2020 9:39 am you do upload from IDE? what are your Tools menu settings?

No, not yet. I am just using ST Cube Programmer at the moment, as I had the first error messages in the Arduino IDE (with the most recent core installed etc.) and then tried to reduce the impacts of other software.

Blink didn't compile?

Compile was no problem, but the upload failed with the very same error. No wonder, since Arduino IDE uses Cube Programmer for it