fix: handle variable stage2.bin file sizes across firmware versions

- Add STAGE2_SIZES mapping for firmware versions with larger stage2.bin files
- Update validate_file_size function to accept firmware version parameter
- Firmware 904, 950, 951 have 6034-byte stage2.bin files (vs 2705 for others)
- All stage1.bin files remain 500 bytes consistently

This resolves the file size validation failures for firmware versions 904, 950, and 951.

Author: SoftwareRat

scripts/firmware-downloader.sh

@@ -32,7 +32,15 @@ declare -A FIRMWARE_MAP=(
 # Expected file sizes (in bytes) for validation
 declare -A EXPECTED_SIZES=(
     ["stage1.bin"]=500
-    ["stage2.bin"]=2705
+    ["stage2.bin"]=2705  # Default size, will be adjusted per firmware version
+)
+
+# Firmware-specific stage2.bin sizes (some versions have larger stage2 files)
+declare -A STAGE2_SIZES=(
+    ["904"]=6034
+    ["950"]=6034
+    ["951"]=6034
+    # All other versions use the default 2705 bytes
 )
 
 # Colors for output
@@ -74,6 +82,7 @@ generate_url() {
 validate_file_size() {
     local file_path="$1"
     local binary_name="$2"
+    local firmware_version="${3:-}"
 
     if [[ ! -f "$file_path" ]]; then
         log_error "File does not exist: $file_path"
@@ -82,7 +91,12 @@ validate_file_size() {
 
     local actual_size
     actual_size=$(stat -c%s "$file_path" 2>/dev/null || stat -f%z "$file_path" 2>/dev/null)
+    
+    # Get expected size based on firmware version and binary type
     local expected_size="${EXPECTED_SIZES[$binary_name]}"
+    if [[ "$binary_name" == "stage2.bin" && -n "$firmware_version" && -n "${STAGE2_SIZES[$firmware_version]:-}" ]]; then
+        expected_size="${STAGE2_SIZES[$firmware_version]}"
+    fi
 
     # Allow some tolerance for file size variations (±10%)
     local min_size=$((expected_size * 90 / 100))
@@ -157,7 +171,7 @@ download_binary() {
     fi
 
     # Validate downloaded file
-    if validate_file_size "$output_path" "$binary_name"; then
+    if validate_file_size "$output_path" "$binary_name" "$firmware_version"; then
         local checksum
         checksum=$(calculate_checksum "$output_path")
         log_success "Downloaded and validated: $binary_name (SHA256: $checksum)"
@@ -229,7 +243,7 @@ verify_firmware_version() {
         return 1
     fi
 
-    if validate_file_size "$stage1_path" "stage1.bin" && validate_file_size "$stage2_path" "stage2.bin"; then
+    if validate_file_size "$stage1_path" "stage1.bin" "$firmware_version" && validate_file_size "$stage2_path" "stage2.bin" "$firmware_version"; then
         log_success "Firmware $firmware_name ($firmware_version) verification passed"
         return 0
     else