Peer review fixes

Makefile

@@ -336,7 +336,7 @@ wolfboot.bin: wolfboot.elf
 	$(Q)$(OBJCOPY) $(OBJCOPY_FLAGS) -O binary $^ $@
 ifeq ($(TARGET),nxp_lpc54s0xx)
 	@echo "\t[LPC] enhanced boot block"
-	$(Q)python3 -c "import struct,os;f=open('$@','r+b');sz=os.path.getsize('$@');f.seek(0x24);f.write(struct.pack('<2I',0xEDDC94BD,0x160));f.seek(0x160);f.write(struct.pack('<25I',0xFEEDA5A5,3,0x10000000,sz-4,0,0,0,0,0,0xEDDC94BD,0,0,0,0x001640EF,0,0,0x1301001D,0,0,0,0x00000100,0,0,0x04030050,0x14110D09));f.seek(0);d=f.read(28);w=struct.unpack('<7I',d);s=sum(w)&0xFFFFFFFF;ck=(0x100000000-s)&0xFFFFFFFF;f.seek(0x1C);f.write(struct.pack('<I',ck));f.close();print('\tvector checksum: 0x%08X'%ck)"
+	$(Q)python3 tools/scripts/lpc54s0xx_patch_boot_block.py $@
 endif
 	@echo
 	@echo "\t[SIZE]"

config/examples/nxp_lpc54s0xx.config

@@ -4,7 +4,7 @@
 # Boot:     ROM boot loads wolfBoot from external SPIFI QSPI flash at 0x10000000
 # HAL:      Bare-metal (hal/nxp_lpc54s0xx.c) — no NXP MCUXpresso SDK required
 #
-# Flash layout (SPIFI QSPI, 16 MB total):
+# Flash layout (SPIFI QSPI, 4 MB total — Winbond W25Q32JV):
 #   0x10000000  wolfBoot (up to BOOT partition base)
 #   0x10010000  BOOT partition   (960 KB, signed application)
 #   0x10100000  UPDATE partition (960 KB)

hal/nxp_lpc54s0xx.c

@@ -440,6 +440,9 @@ static void RAMFUNCTION spifi_wait_busy(void)
     SPIFI_IDATA = 0x00;                        /* expect BUSY=0 */
     SPIFI_CLIMIT = (saved_climit & 0xFFFFFF00) | W25Q_STATUS_BUSY; /* mask bit 0 */
 
+    /* Callers (hal_flash_write / hal_flash_erase) always issue a non-MCMD
+     * command before reaching here, so MCINIT is clear and the reset path in
+     * spifi_set_cmd() does not run — IDATA/CLIMIT programmed above survive. */
     spifi_set_cmd(CMD_READ_STATUS);             /* POLL mode command */
 
     /* SPIFI hardware polls flash status internally.

test-app/syscalls.c

@@ -22,9 +22,15 @@
  */
 
 #include <stdint.h>
+#include <stddef.h>
 #include <stdarg.h>
 #include <sys/stat.h>
 
+/* Forward declaration of vsnprintf. We intentionally do not include <stdio.h>
+ * because this file redefines stdout/stderr/fputs/fflush with bare-metal
+ * (void *) stubs that collide with the libc FILE-based prototypes. */
+extern int vsnprintf(char *str, size_t size, const char *fmt, va_list ap);
+
 /* Provide our own errno for bare-metal.
  * Using the libc errno via <errno.h> can conflict with TLS-based errno
  * on cross-toolchains (e.g. powerpc-linux-gnu glibc). */

tools/scripts/lpc54s0xx_patch_boot_block.py

@@ -0,0 +1,86 @@
+#!/usr/bin/env python3
+# lpc54s0xx_patch_boot_block.py
+#
+# Patch a wolfBoot binary for the NXP LPC540xx / LPC54S0xx SPIFI (XIP) boot
+# ROM. The ROM expects an "enhanced boot block":
+#   - offset 0x1C:  vector table checksum (negated sum of the first 7 words)
+#   - offset 0x24:  boot block marker + offset to descriptor
+#   - offset 0x160: 25-word descriptor (magic, mode, image base, image size, ...)
+#
+# Usage: lpc54s0xx_patch_boot_block.py <wolfboot.bin>
+#
+# Copyright (C) 2025 wolfSSL Inc.
+# This file is part of wolfBoot (GPL-2.0-or-later).
+
+import os
+import struct
+import sys
+
+HEADER_MARKER_OFFSET = 0x24
+BOOT_BLOCK_OFFSET    = 0x160
+VECTOR_CHECKSUM_OFFSET = 0x1C
+IMAGE_BASE_ADDR      = 0x10000000  # SPIFI XIP base
+
+HEADER_MARKER_FMT  = "<2I"          # 0xEDDC94BD, 0x160
+BOOT_BLOCK_FMT     = "<25I"
+VECTOR_TABLE_FMT   = "<7I"          # first 7 words covered by checksum
+
+
+def patch(path):
+    size = os.path.getsize(path)
+    header_marker_size = struct.calcsize(HEADER_MARKER_FMT)
+    boot_block_size    = struct.calcsize(BOOT_BLOCK_FMT)
+    vector_table_size  = struct.calcsize(VECTOR_TABLE_FMT)
+
+    min_size = max(
+        vector_table_size,
+        HEADER_MARKER_OFFSET + header_marker_size,
+        BOOT_BLOCK_OFFSET + boot_block_size,
+    )
+    if size < min_size:
+        raise SystemExit(
+            "error: %s is too small for LPC54S0xx boot block patching "
+            "(size=%d, need at least %d bytes)" % (path, size, min_size)
+        )
+
+    with open(path, "r+b") as f:
+        f.seek(HEADER_MARKER_OFFSET)
+        f.write(struct.pack(HEADER_MARKER_FMT, 0xEDDC94BD, BOOT_BLOCK_OFFSET))
+
+        f.seek(BOOT_BLOCK_OFFSET)
+        f.write(struct.pack(
+            BOOT_BLOCK_FMT,
+            0xFEEDA5A5,      # magic
+            3,               # image type
+            IMAGE_BASE_ADDR, # image base
+            size - 4,        # image size (minus CRC slot)
+            0, 0, 0, 0, 0,
+            0xEDDC94BD,      # header marker echo
+            0, 0, 0,
+            0x001640EF,      # SPIFI config
+            0, 0,
+            0x1301001D,      # clock/flash timing word
+            0, 0, 0,
+            0x00000100,      # options
+            0, 0,
+            0x04030050,      # PLL config
+            0x14110D09,      # clock divider config
+        ))
+
+        f.seek(0)
+        words = struct.unpack(VECTOR_TABLE_FMT, f.read(vector_table_size))
+        checksum = (0x100000000 - (sum(words) & 0xFFFFFFFF)) & 0xFFFFFFFF
+        f.seek(VECTOR_CHECKSUM_OFFSET)
+        f.write(struct.pack("<I", checksum))
+
+    print("\tvector checksum: 0x%08X" % checksum)
+
+
+def main(argv):
+    if len(argv) != 2:
+        raise SystemExit("usage: %s <wolfboot.bin>" % argv[0])
+    patch(argv[1])
+
+
+if __name__ == "__main__":
+    main(sys.argv)

tools/scripts/nxp-lpc54s0xx-flash.sh

@@ -30,6 +30,7 @@
 #
 
 set -e
+set -o pipefail
 
 # Configuration (can be overridden via environment variables)
 CONFIG_FILE="${CONFIG_FILE:-config/examples/nxp_lpc54s0xx.config}"
@@ -110,10 +111,15 @@ parse_config() {
         exit 1
     fi
 
-    # Helper function to extract config value
+    # Helper function to extract config value.
+    # Anchor the regex to `KEY=` or `KEY?=` so e.g. SIGN does not match SIGN_ALG.
+    # grep with --max-count=1 keeps the pipeline single-stage so pipefail catches
+    # a truly missing key (exit 1) rather than relying on `head` to mask it.
     get_config_value() {
         local key="$1"
-        grep -E "^${key}" "$config_file" | head -1 | sed -E "s/^${key}\??=//" | tr -d '[:space:]'
+        local line
+        line=$(grep -E "^${key}\\??=" "$config_file" --max-count=1) || return 0
+        printf '%s' "${line#*=}" | tr -d '[:space:]'
     }
 
     # Extract SIGN and HASH
@@ -146,9 +152,9 @@ parse_config() {
 
     # Ensure partition addresses have 0x prefix for bash arithmetic
     for var in WOLFBOOT_PARTITION_BOOT_ADDRESS WOLFBOOT_PARTITION_UPDATE_ADDRESS WOLFBOOT_PARTITION_SIZE WOLFBOOT_SECTOR_SIZE; do
-        eval "val=\$$var"
+        local val="${!var}"
         if [[ ! "$val" =~ ^0x ]]; then
-            eval "$var=\"0x\${val}\""
+            printf -v "$var" '0x%s' "$val"
         fi
     done