Allow to skip padding when building flash image

Author: Janrupf

cargo-espflash/src/main.rs

@@ -124,6 +124,9 @@ pub struct SaveImageOpts {
     /// Custom partition table for merging
     #[clap(long, short = 'T')]
     pub partition_table: Option<PathBuf>,
+    /// Don't pad the image to the flash size
+    #[clap(long, short = 'P')]
+    pub skip_padding: bool,
 }
 
 fn main() -> Result<()> {
@@ -423,6 +426,7 @@ fn save_image(
         opts.merge,
         bootloader,
         partition_table,
+        opts.skip_padding,
     )?;
 
     Ok(())

espflash/src/cli/mod.rs

@@ -172,6 +172,7 @@ pub fn save_elf_as_image(
     merge: bool,
     bootloader_path: Option<PathBuf>,
     partition_table_path: Option<PathBuf>,
+    skip_padding: bool,
 ) -> Result<()> {
     let image = ElfFirmwareImage::try_from(elf_data)?;
 
@@ -237,13 +238,15 @@ pub fn save_elf_as_image(
             file.write_all(&segment.data).into_diagnostic()?;
         }
 
-        // Take flash_size as input parameter, if None, use default value of 4Mb
-        let padding_bytes = vec![
-            0xffu8;
-            flash_size.unwrap_or(FlashSize::Flash4Mb).size() as usize
-                - file.metadata().into_diagnostic()?.len() as usize
-        ];
-        file.write_all(&padding_bytes).into_diagnostic()?;
+        if !skip_padding {
+            // Take flash_size as input parameter, if None, use default value of 4Mb
+            let padding_bytes = vec![
+                0xffu8;
+                flash_size.unwrap_or(FlashSize::Flash4Mb).size() as usize
+                    - file.metadata().into_diagnostic()?.len() as usize
+            ];
+            file.write_all(&padding_bytes).into_diagnostic()?;
+        }
     } else {
         let flash_image = chip.get_flash_image(
             &image,

espflash/src/main.rs

@@ -79,6 +79,9 @@ pub struct SaveImageOpts {
     /// Custom partition table for merging
     #[clap(long, short = 'T')]
     pub partition_table: Option<PathBuf>,
+    /// Don't pad the image to the flash size
+    #[clap(long, short = 'P')]
+    pub skip_padding: bool,
 }
 
 fn main() -> Result<()> {
@@ -197,6 +200,7 @@ fn save_image(opts: SaveImageOpts) -> Result<()> {
         opts.merge,
         opts.bootloader,
         opts.partition_table,
+        opts.skip_padding,
     )?;
 
     Ok(())