Sometimes the chip enters a state where the debug interface is frozen. A standard "Unlock" command isn't enough; the chip needs a full power cycle or a reset under specific conditions.
Ensure any "Write Protect" (WP) jumpers or switches on the board are off. writing flash programmer... fail unlock tool
# Find the device def find_device(vid, pid): return usb.core.find(idVendor=vid, idProduct=pid) Sometimes the chip enters a state where the
Many chips have multiple programming interfaces (e.g., JTAG, SWD, UART, or USB-DFU). pid): return usb.core.find(idVendor=vid
If the normal tool fails, drop down to raw memory access. Do not attempt to "Program & Verify." Instead: