Improve bootloader and partitions file detection in prepare-firmware.sh

Enhanced file discovery to handle various PlatformIO/ESP-IDF directory structures:

**Problem:** The script may fail to find bootloader.bin and partitions.bin if
they're in unexpected locations within the build directory.

**Improvements:**

1. **Enhanced file search function:**
   - Checks multiple possible locations for each file
   - Shows exactly which paths are being checked
   - Reports which location succeeded
   - Falls back to recursive search if standard locations fail

2. **Extended search paths:**
   - bootloader.bin: 3 locations checked
     - BUILD_DIR/bootloader.bin (ESP-IDF v3.x)
     - BUILD_DIR/bootloader/bootloader.bin (ESP-IDF v4.x)
     - BUILD_DIR/esp-idf/bootloader/bootloader.bin (some configs)
   - partitions.bin: 2 locations checked
     - BUILD_DIR/partitions.bin (standard)
     - BUILD_DIR/partitions/partitions.bin (alternative)

3. **Better debugging output:**
   - Shows search progress for each file
   - If file not found in expected locations, performs recursive search
   - Displays first 50 lines of build directory structure
   - Clear indication of which files are found vs missing

4. **Improved error messages:**
   - Lists all checked locations before failing
   - Shows actual filesystem structure to aid diagnosis
   - Provides actionable troubleshooting steps
   - Helps identify if files are in unexpected locations

This ensures the script works across different PlatformIO and ESP-IDF
versions, and provides clear diagnostic information when files can't be found.

Co-authored-by: softhack007 <91616163+softhack007@users.noreply.github.com>

Author: Copilot

test/wokwi/prepare-firmware.sh

@@ -20,53 +20,109 @@ BUILD_DIR="$PROJECT_ROOT/.pio/build/$ENV_NAME"
 FIRMWARE_BIN="$BUILD_DIR/firmware.bin"
 FIRMWARE_ELF="$BUILD_DIR/firmware.elf"
 
-# PlatformIO stores bootloader and partitions in the build directory
-# but they might be in subdirectories depending on the platform version
-BOOTLOADER_BIN="$BUILD_DIR/bootloader.bin"
-PARTITIONS_BIN="$BUILD_DIR/partitions.bin"
-
-# Alternative locations for bootloader (ESP-IDF v4+ might use different paths)
-if [ ! -f "$BOOTLOADER_BIN" ]; then
-    ALT_BOOTLOADER="$BUILD_DIR/bootloader/bootloader.bin"
-    if [ -f "$ALT_BOOTLOADER" ]; then
-        BOOTLOADER_BIN="$ALT_BOOTLOADER"
-    fi
+echo "=== Preparing firmware for Wokwi simulation ==="
+echo "Environment: $ENV_NAME"
+echo "Build directory: $BUILD_DIR"
+echo ""
+
+# Check if build directory exists
+if [ ! -d "$BUILD_DIR" ]; then
+    echo "❌ ERROR: Build directory not found: $BUILD_DIR"
+    echo "Please build the firmware first: pio run -e $ENV_NAME"
+    exit 1
 fi
 
-# Check if required files exist
-MISSING_FILES=""
+echo "Searching for required files in build directory..."
+echo ""
 
-if [ ! -f "$FIRMWARE_BIN" ]; then
-    echo "❌ ERROR: Firmware binary not found at $FIRMWARE_BIN"
-    MISSING_FILES="${MISSING_FILES}firmware.bin "
-fi
+# Function to find file with multiple possible locations
+find_file() {
+    local file_desc=$1
+    shift
+    local found_file=""
+    
+    echo "Looking for $file_desc:"
+    for path in "$@"; do
+        echo "  Checking: $path"
+        if [ -f "$path" ]; then
+            found_file="$path"
+            echo "  ✓ Found at: $path"
+            echo "$found_file"
+            return 0
+        fi
+    done
+    
+    echo "  ❌ Not found in any expected location"
+    return 1
+}
 
-if [ ! -f "$BOOTLOADER_BIN" ]; then
-    echo "❌ ERROR: bootloader.bin not found!"
-    echo "   Checked: $BUILD_DIR/bootloader.bin"
-    echo "   Also checked: $BUILD_DIR/bootloader/bootloader.bin"
-    MISSING_FILES="${MISSING_FILES}bootloader.bin "
-fi
+# Find firmware.bin
+FIRMWARE_BIN=$(find_file "firmware.bin" \
+    "$BUILD_DIR/firmware.bin") || {
+    echo ""
+    echo "❌ ERROR: firmware.bin not found"
+    FIRMWARE_BIN=""
+}
+echo ""
 
-if [ ! -f "$PARTITIONS_BIN" ]; then
-    echo "❌ ERROR: partitions.bin not found at $PARTITIONS_BIN"
-    MISSING_FILES="${MISSING_FILES}partitions.bin "
-fi
+# Find bootloader.bin - check multiple common locations
+BOOTLOADER_BIN=$(find_file "bootloader.bin" \
+    "$BUILD_DIR/bootloader.bin" \
+    "$BUILD_DIR/bootloader/bootloader.bin" \
+    "$BUILD_DIR/esp-idf/bootloader/bootloader.bin") || {
+    echo ""
+    echo "❌ ERROR: bootloader.bin not found"
+    echo "Searching entire build directory for bootloader.bin:"
+    find "$BUILD_DIR" -name "bootloader.bin" -type f 2>/dev/null | while read f; do
+        echo "  Found: $f"
+    done
+    BOOTLOADER_BIN=""
+}
+echo ""
 
-if [ -n "$MISSING_FILES" ]; then
+# Find partitions.bin - check multiple common locations
+PARTITIONS_BIN=$(find_file "partitions.bin" \
+    "$BUILD_DIR/partitions.bin" \
+    "$BUILD_DIR/partitions/partitions.bin") || {
     echo ""
+    echo "❌ ERROR: partitions.bin not found"
+    echo "Searching entire build directory for partitions.bin:"
+    find "$BUILD_DIR" -name "partitions.bin" -type f 2>/dev/null | while read f; do
+        echo "  Found: $f"
+    done
+    PARTITIONS_BIN=""
+}
+echo ""
+
+# Check if any files are missing
+MISSING_FILES=""
+[ -z "$FIRMWARE_BIN" ] && MISSING_FILES="${MISSING_FILES}firmware.bin "
+[ -z "$BOOTLOADER_BIN" ] && MISSING_FILES="${MISSING_FILES}bootloader.bin "
+[ -z "$PARTITIONS_BIN" ] && MISSING_FILES="${MISSING_FILES}partitions.bin "
+
+if [ -n "$MISSING_FILES" ]; then
     echo "❌ ERROR: Missing required files: $MISSING_FILES"
     echo ""
-    echo "Build directory contents:"
-    ls -la "$BUILD_DIR" | head -20
+    echo "Build directory structure:"
+    echo "----------------------------------------"
+    ls -lR "$BUILD_DIR" | head -50
+    echo "----------------------------------------"
     echo ""
     echo "These files are generated by PlatformIO/ESP-IDF during the build process."
-    echo "To fix this issue:"
+    echo ""
+    echo "Troubleshooting steps:"
     echo "1. Ensure the build completed successfully: pio run -e $ENV_NAME"
-    echo "2. Verify the partition table is correctly specified in platformio.ini"
+    echo "2. Check for build errors in PlatformIO output"
+    echo "3. Verify partition table is specified in platformio.ini"
+    echo "4. For ESP-IDF framework, bootloader should be auto-generated"
+    echo ""
+    echo "If files are in unexpected locations, the script will show them above."
     exit 1
 fi
 
+echo "✅ All required files found!"
+echo ""
+
 echo "Creating combined firmware image for Wokwi..."
 echo "Using files from $ENV_NAME build:"
 echo "  - Bootloader: $(basename $(dirname "$BOOTLOADER_BIN"))/$(basename "$BOOTLOADER_BIN")"