Blue Pill

stm32_blue_pill

Clone Chip Lotto.

Either a genuine STM32 chip or a cheap knockoff. Did you win the lottery?

Good to know

NO USB bootloader from the factory – first flash via ST-LINK or serial (BOOT0=1).
The infamous R10: the USB pull-up resistor has the wrong value on many clones (should be 1.5k) – without fixing it USB will not enumerate.
BOOT0/BOOT1 jumpers select the boot mode; the PC13 LED is sink-wired.
The 3.3V regulator is weak, and the chip itself may be a CS32/GD32 clone.