update README

README.md

@@ -1,15 +1,24 @@
 # bmap-writer
 
-## Build
+`bmap-writer` is a command-line utility designed to efficiently write disk images to storage devices using block mapping (BMAP). 
+It serves as a lightweight alternative to the Yocto BMAP tool, specifically for embedded systems. 
+Unlike the Yocto BMAP tool, `bmap-writer` is C++ based does not require Python and focuses solely on writing an image.
 
-```
-cmake .
+## Key Features
 
-make 
-```
+- **Alternative to Yocto BMAP Tool**: Provides a lightweight alternative specifically for embedded systems.
+- **No Python Required**: Does not require Python, making it easier to integrate into various environments.
+- **Support for Compressed Images**: Handles gzip and xz compressed images, decompressing them on-the-fly during the writing process.
+- **Checksum Verification**: Ensures data integrity by verifying checksums for each block.
+- **Efficient Writing**: Writes only the necessary blocks, reducing the overall write time and wear on storage devices.
+
+## How It Works
 
-## Usage
+1. **Generate a BMAP File**: Create a BMAP file for your disk image using `bmaptool`.
+2. **Write the Image**: Use `bmap-writer` to write the image to your target device, specifying the BMAP file for efficient block mapping.
+
+## Example Usage
 
 ```
 bmap-writer <image-file> <bmap-file> <target-device>
-```
+```