Update README.md

Specifying output folder name is optional

Author: CaptainThrowback

README.md

@@ -2,13 +2,17 @@
 
 - Python3, pip
 - google protobuf for python `pip3 install protobuf`
+- six `pip3 install six`
 
 ### Full OTA
-
-- ./extract.py [--skip_hash] --output_dir output/ payload.bin
-- This will start to extract the images within the payload.bin file to the output folder you are in.
+```
+./extract.py [--skip_hash] [--output_dir] payload.bin
+```
+- This will start to extract the images within the payload.bin file to a folder named "output" by default (a different folder name can be specified).
 
 ### Incremental OTA
 
 - Copy original images (from full OTA or dumped from devices) to old folder
-- ./extract.py [--skip_hash] --output_dir output/ --old_dir old/ payload.bin
+```
+./extract.py [--skip_hash] [--output_dir] --old_dir <old-dir-name> payload.bin
+```