README: update documentation for ramdisk_compression variable

README.md

@@ -22,6 +22,7 @@ device.name3=toroplus
 
 block=/dev/block/platform/omap/omap_hsmmc.0/by-name/boot;
 is_slot_device=0;
+ramdisk_compression=auto;
 ```
 
 __do.devicecheck=1__ specified requires at least device.name1 to be present. This should match ro.product.device or ro.build.product for your device. There is support for up to 5 device.name# properties.
@@ -34,6 +35,8 @@ __do.cleanuponabort=0__ will keep the zip from removing it's working directory i
 
 `is_slot_device=1` enables detection of the suffix for the active boot partition on slot-based devices and will add this to the end of the supplied `block=` path.
 
+`ramdisk_compression=auto` allows automatically repacking the ramdisk with the format detected during unpack, changing `auto` to `gz`, `lzo`, `lzma`, `xz`, `bz2`, `lz4`, or `lz4-l` (for lz4 legacy) instead forces the repack as that format.
+
 ## // Command Methods ##
 ```
 dump_boot