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To support UART RX using the same USB device, we can reflash the STM32F101 on the programmer. Interestingly, they're treated as STM32F103s, as 101s don't officially have a USB core.
The alternative new programmer firmware is dap42, which supports SWD and UART RX on the SWIM pin. To program the programmer, follow the instructions here. This link shows the programming pinout.