I have the same problem.
Without interrupt no have problem, but with interrupt I need to increase CPU clock above to 48Mhz.
In my case, need:
Put BOOT0 to 1
Press reset of MCU
With St Link Utility, press “Connect”
Upload firmware
Put BOOT0 to 0
and reset.
SOLVED
open with notepad or any text editor
MY_DRIVE:\\STM32Toolchain\openocd\scripts\board\st_nucleo_f103rb.cfg
and edit:
source [find interface/stlink-v2-1.cfg]
to source [find interface/stlink-v2.cfg]
for chinese ST-LINK v2