diff --git a/README.md b/README.md
new file mode 100644
index 0000000..33978e0
--- /dev/null
+++ b/README.md
@@ -0,0 +1,34 @@
+# menhera.sh
+
+Start a RAM Linux system (Debian for now) without requiring physical access to your server.
+
+With menhera.sh you can:
+  * format your system disk or create RAID
+  * install a new distro
+  * do important maintenance or backup with nobody writing to your root filesystem
+  * ...
+
+with only SSH!
+
+"menhera" is short for "mental healer". 
+
+## Dependencies
+
+  * Linux kernel: overlayfs and tmpfs support
+  * systemd
+  * squashfs-tools
+  * wget
+
+## Usage
+
+Just download and run.
+
+## Known issues
+
+  * Cannot auto detect rootfs URL
+
+## Thanks
+
+  * This project is inspired by [marcan/takeover.sh](https://github.com/marcan/takeover.sh)
+  * The major code came from [a maintenance writeup on my blog](https://blog.swineson.me/debian-9-csm-online-convert-root-partition-to-raid/) (in Simp. Chinese)
+  * [xTom.com](https://xtom.com/) donated a VPS for my testing
\ No newline at end of file
diff --git a/menhera.sh b/menhera.sh
index e997eb0..047dfce 100755
--- a/menhera.sh
+++ b/menhera.sh
@@ -3,7 +3,7 @@ set -Eeuo pipefail
 
 # config
 WORKDIR="/tmp/menhera"
-ROOTFS="https://images.linuxcontainers.org/images/debian/stretch/amd64/default/20190409_05:24/rootfs.squashfs"
+ROOTFS=""
 
 # internal global variables
 OLDROOT="/"
@@ -23,6 +23,16 @@ confirm() {
     esac
 }
 
+get_rootfs() {
+    if [ -z ${ROOTFS+x} ]; then 
+        echo "Getting rootfs URL..."
+        ROOTFS_TIME=$(curl "https://uk.images.linuxcontainers.org/images/debian/stretch/amd64/default/?C=M;O=D" | grep "folder.gif" | head -n 1 | cut -d'>' -f7 | cut -d'/' -f1)
+        ROOTFS="https://images.linuxcontainers.org/images/debian/stretch/amd64/default/${ROOTFS_TIME}/rootfs.squashfs"
+    else 
+        echo "\$ROOTFS is set to '$ROOTFS'"
+    fi
+}
+
 sync_filesystem() {
     echo "Syncing..."
     sync
@@ -135,6 +145,7 @@ echo -e "\tYou have closed all programs you can, and backed up all important dat
 echo -e "\tYou can SSH into your system as root user"
 confirm || exit -1
 
+get_rootfs
 sync_filesystem
 
 prepare_environment