docs: add pyocd docs

README.md

@@ -71,6 +71,37 @@ When using an external debugger, you can flash using this command:
 west flash --erase
 ```
 
+Experimental: You can also use [pyOCD](https://github.com/pyocd/pyOCD) to flash the nRF9151 using the CMSIS-DAP interface provided by the Connectivity Bridge firmware.
+
+Note: **Don't use pyOCD with JLink probes**, use [nrfutil-device](https://docs.nordicsemi.com/bundle/nrfutil/page/README.html) or the west runner in that case. pyOCD seems to be unmaintained at the moment, so this might not be fixed.
+
+Another note: Sometimes, the nRF9151 is detected as protected and is mass-erased automatically. In that case, simply flash the bootloader as well.
+
+To flash just the app:
+
+```
+pyocd flash build/app/zephyr/zephyr.signed.hex
+```
+
+To flash the bootloader (included in releases):
+
+```
+pyocd flash nrf91-bl-v2.hex
+```
+
+To erase the chip including UICR:
+
+```
+pyocd erase --mass
+```
+
+Experimental: You can update the modem firmware using pyOCD. A simple way to do this is to use the included `nrf91_flasher` script:
+
+```
+python3 scripts/nrf91_flasher.py -m mfw_nrf91x1_2.0.1.zip
+```
+
+
 ### LED pattern
 
 | LED effect     | Color      | Meaning                                      | Duration (seconds)                                  |

scripts/nrf91_flasher.py

@@ -0,0 +1,89 @@
+#!/usr/bin/env python3
+#
+# Copyright (c) 2024 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+
+from pyocd.core.helpers import ConnectHelper
+from pyocd.flash.file_programmer import FileProgrammer
+from pyocd.core.target import Target
+from pyocd.target.family.target_nRF91 import ModemUpdater
+from pyocd.core.exceptions import TargetError
+from intelhex import IntelHex
+from tempfile import TemporaryDirectory
+import os
+from timeit import default_timer as timer
+import argparse
+
+import logging
+logging.basicConfig(level=logging.INFO)
+
+parser = argparse.ArgumentParser(description="Wrapper around pyOCD to flash nRF91")
+parser.add_argument("-e", "--erase", help = "perform mass_erase", action='store_true')
+parser.add_argument("-p", "--program", help = "program file (hex, elf, bin)")
+parser.add_argument("-m", "--modem", help = "modem update zip file")
+parser.add_argument("-u", "--uid", help = "probe uid")
+
+args = parser.parse_args()
+
+options = {
+    "target_override" : "nrf91",
+    "cmsis_dap.limit_packets" : False,
+    "frequency" : 8000000,
+    "logging" : {
+	"loggers": {
+		"pyocd.coresight" : {"level": logging.INFO}
+	}
+    }
+}
+
+with ConnectHelper.session_with_chosen_probe(unique_id=args.uid, options=options) as session:
+
+    board = session.board
+    target = board.target
+    flash = target.memory_map.get_boot_memory()
+
+    if args.erase:
+        logging.info("perform mass erase")
+        target.mass_erase()
+
+    if args.program:
+        if args.program.endswith("hex"):
+            # Load firmware into device.
+            logging.info("flashing program")
+            input = IntelHex(args.program)
+            flash = input[0x00000000:0x00100000]
+            uicr  = input[0x00FF8000:0x00FF9000]
+            with TemporaryDirectory() as tempdir:
+                if len(uicr.segments()) > 0:
+                    logging.info("writing UICR")
+                    for start, end in uicr.segments():
+                        target.write_flash(start, uicr[start:end].tobinarray())
+
+                logging.info("writing flash")
+                flash_file = os.path.join(tempdir, "flash.hex")
+                flash.tofile(flash_file, format="hex")
+                FileProgrammer(session).program(flash_file)
+        else:
+            logging.info("not a HEX file, flashing without range checks")
+            FileProgrammer(session).program(args.program)
+
+    if args.modem:
+        modem_needs_update = False
+
+        # Check modem firmware version
+        try:
+            ModemUpdater(session).verify(args.modem)
+        except TargetError as e:
+            modem_needs_update = True
+
+        # Update modem firmware.
+        if modem_needs_update:
+            logging.warning("modem verify failed, updating modem firmware")
+            start = timer()
+            ModemUpdater(session).program_and_verify(args.modem)
+            end = timer()
+            logging.info(f"modem update took {end-start} seconds")
+    # Reset, run.
+    logging.info("resetting device")
+    target.reset()