Verify RP2040 capabilities against matching UF2 application

scripts/check_firmware_capabilities.py

@@ -11,6 +11,7 @@ import sys
 import struct
 import zipfile
 import zlib
+from rp2040_application import read_application as read_rp2040_application
 from package_meshtext_license import (CAPABILITY as MESHTEXT_CAPABILITY,
     meshtext_evidence, notice_bytes as meshtext_notice_bytes,
     notice_record as meshtext_notice_record)
@@ -81,6 +82,7 @@ def parse_args() -> argparse.Namespace:
     parser.add_argument("--firmware-bin", type=Path)
     parser.add_argument("--partitions", type=Path)
     parser.add_argument("--dfu-package", type=Path)
+    parser.add_argument("--uf2-package", type=Path)
     parser.add_argument(
         "--expect",
         action="append",
@@ -96,7 +98,7 @@ def parse_args() -> argparse.Namespace:
     parser.add_argument(
         "--expect-application", action="append", default=[],
         metavar="CAPABILITY=TEXT",
-        help="Require TEXT in the packaged firmware.bin or DFU application, not ELF metadata.",
+        help="Require TEXT in the packaged BIN, DFU application, or verified RP2040 UF2 application, not ELF metadata.",
     )
     return parser.parse_args()
 
@@ -124,6 +126,10 @@ def linked_gzip_assets(image):
 
 
 def read_application(args):
+    if args.platform == "RP2040_PLATFORM" or args.uf2_package is not None:
+        if args.platform != "RP2040_PLATFORM" or args.uf2_package is None or args.firmware_bin is None:
+            raise ValueError("RP2040 application checks require both --uf2-package and --firmware-bin")
+        return read_rp2040_application(args.uf2_package, args.firmware_bin)
     if args.firmware_bin is not None:
         return args.firmware_bin.read_bytes()
     if args.dfu_package is not None:

scripts/rp2040_application.py

@@ -0,0 +1,49 @@
+"""Verify that an RP2040 UF2 carries the exact application offered as BIN."""
+from pathlib import Path
+import struct
+
+BLOCK_BYTES = 512
+PAYLOAD_BYTES = 256
+FLASH_BASE = 0x10000000
+FLASH_END = 0x11000000  # RP2040's maximum 16 MiB XIP flash window.
+FAMILY = 0xE48BFF56
+
+
+def read_application(uf2_path: Path, bin_path: Path) -> bytes:
+    """Return real flash bytes, excluding UF2 headers and alignment padding.
+
+    Both public formats must agree. ELF strings, unused sector bytes, and
+    bytes outside the BIN's application extent cannot supply capability proof.
+    The board's ordinary linker/size checks retain its stricter flash limit.
+    """
+    size = uf2_path.stat().st_size
+    if not size or size % BLOCK_BYTES or size > (FLASH_END - FLASH_BASE) * 2:
+        raise ValueError("RP2040 UF2 has an invalid sector extent")
+    application_size = bin_path.stat().st_size
+    if not 0 < application_size <= FLASH_END - FLASH_BASE:
+        raise ValueError("RP2040 BIN is empty or exceeds the XIP flash window")
+    data = uf2_path.read_bytes()
+    if len(data) != size:
+        raise ValueError("RP2040 UF2 changed during application qualification")
+    count = size // BLOCK_BYTES
+    payload = bytearray()
+    for index in range(count):
+        offset = index * BLOCK_BYTES
+        magic0, magic1, flags, address, length, number, total, family = struct.unpack_from("<8I", data, offset)
+        trailer = struct.unpack_from("<I", data, offset + 508)[0]
+        if (magic0, magic1, trailer) != (0x0A324655, 0x9E5D5157, 0x0AB16F30):
+            raise ValueError("RP2040 UF2 has an invalid sector header/trailer")
+        if flags != 0x2000 or family != FAMILY:
+            raise ValueError("RP2040 UF2 must contain only main-flash blocks with the RP2040 family")
+        if length != PAYLOAD_BYTES or number != index or total != count:
+            raise ValueError("RP2040 UF2 has inconsistent payload lengths or block numbers")
+        if address != FLASH_BASE + index * PAYLOAD_BYTES or address + length > FLASH_END:
+            raise ValueError("RP2040 UF2 has gaps, overlaps, or addresses outside its XIP flash window")
+        payload.extend(data[offset + 32:offset + 32 + length])
+    application = bin_path.read_bytes()
+    tail = payload[application_size:]
+    if len(payload) < application_size or len(tail) >= PAYLOAD_BYTES or payload[:application_size] != application:
+        raise ValueError("RP2040 UF2 application does not match the packaged BIN")
+    if tail and set(tail) not in ({0}, {255}):
+        raise ValueError("RP2040 UF2 has nonuniform application-alignment padding")
+    return bytes(payload[:application_size])