Update README.md

Adding nvs related stuff

Author: lynerc

README.md

@@ -7,6 +7,7 @@ There are three actions:
 - **show_partitions** - will display all of the partitions found in an image file.
 - **dump_partition** - will dump the raw bytes of a specified partition into a file.
 - **create_elf** - reconstruct an ELF file from an 'app' partition (e.g. ota_0).
+- **dump_nvs** - will parse a specified NVS partition and dump its contents.
 
 # Setup
 `pip install -r requirements.txt`
@@ -28,3 +29,11 @@ Dumps to ble_data.dump
 Converts ota_0 partition into ELF. Writes to ota_0.elf
 
 `$ python3 esp32_image_parser.py create_elf espwroom32.bin -partition ota_0 -output ota_0.elf`
+
+## Dump a specific NVS partition
+Dumps the nvs partition
+
+`$ python3 esp32_image_parser.py dump_nvs esp32_flashdump.bin -partition nvs`
+
+Dumps the nvs partition as a JSON
+`$ python3 esp32_image_parser.py dump_nvs flashdump/esp32_flashdump.bin -partition nvs -nvs_output_type json`