adapter driver ftdi
adapter speed     10000
ftdi_vid_pid 0x0403 0x6010
adapter srst pulse_width 10
reset_config srst_only srst_open_drain

ftdi_layout_init 0x0020 0x001b
ftdi_layout_signal nSRST -oe 0x0020 -data 0x0020

source [find target/gd32vf103.cfg]

flash bank $_CHIPNAME.flash gd32vf103 0x08000000 0 0 0 $_TARGETNAME