Hello,

I have bought this product on Amazon which is more expensive (but you can send it back freely on amazon if necessary) :
https://www.amazon.fr/gp/product/B07TSKNWQQ/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1
It is provided with STM32 chip and Onstep is flashing/working well (I think so it is 128K, despite of ST-LINK utility declare 64K).

Thanks.