no serial port and flashing led

[Torsten Curdt]

This is what I tried

$ st-info --probe
Found 1 stlink programmers
  version:    V2J17S4
  serial:     54FF67064882565217411887
  flash:      65536 (pagesize: 1024)
  sram:       20480
  chipid:     0x0410
  descr:      F1xx Medium-density
$ st-flash write hid_generic_pc13.bin 0x8000000
st-flash 1.7.0
2023-02-25T22:41:56 INFO common.c: F1xx Medium-density: 20 KiB SRAM, 64 KiB flash in at least 1 KiB pages.
file hid_generic_pc13.bin md5 checksum: 7133ed5a7f7b88974ece60a3432145d, stlink checksum: 0x0002b428
2023-02-25T22:41:56 INFO common.c: Attempting to write 1976 (0x7b8) bytes to stm32 address: 134217728 (0x8000000)
2023-02-25T22:41:56 INFO common.c: Flash page at addr: 0x08000000 erased
2023-02-25T22:41:57 INFO common.c: Flash page at addr: 0x08000400 erased
2023-02-25T22:41:57 INFO common.c: Finished erasing 2 pages of 1024 (0x400) bytes
2023-02-25T22:41:57 INFO common.c: Starting Flash write for VL/F0/F3/F1_XL
2023-02-25T22:41:57 INFO flash_loader.c: Successfully loaded flash loader in sram
2023-02-25T22:41:57 INFO flash_loader.c: Clear DFSR
  2/  2 pages written
2023-02-25T22:41:57 INFO common.c: Starting verification of write complete
2023-02-25T22:41:57 INFO common.c: Flash written and verified! jolly good!

but the LED is just flashing and there is no usb serial port when connected via USB.

What am I missing?