diff --git a/defaultenv/bin/_boot_help b/defaultenv/bin/_boot_help
new file mode 100644
index 0000000..e7f7f16
--- /dev/null
+++ b/defaultenv/bin/_boot_help
@@ -0,0 +1,18 @@
+#!/bin/sh
+
+echo "boot: boot [-m <mode>] [-k <kernel_option>] [-r <rootfs_option>] [-i <ip_mode>]"
+echo ""
+echo "options"
+echo " - kernel        nand, nor, nfs, tftp, disk"
+echo " - rootfs        nand, nor, net, disk"
+echo " - ip            dhcp, none, empty"
+echo ""
+echo "mode option"
+echo "   mode       kernel      rootfs"
+echo "   nand       nand        nand"
+echo "   nor        nor         nor"
+echo "   nfs        nfs         net"
+echo "   tftp       fttp        net"
+echo "   disk       disk        disk"
+echo ""
+echo "default mode are used from the /env/config"
diff --git a/defaultenv/bin/boot b/defaultenv/bin/boot
index 1120757..d37eca8 100644
--- a/defaultenv/bin/boot
+++ b/defaultenv/bin/boot
@@ -6,19 +6,35 @@
 	kernel_loc=tftp
 fi
 
-if [ x$1 = xnand ]; then
+while getopt "hk:r:i:m:" Option
+do
+if [ ${Option} = k ]; then
+	kernel_loc=${OPTARG}
+elif [ ${Option} = r ]; then
+	rootfs_loc=${OPTARG}
+elif [ ${Option} = i ]; then
+	ip=${OPTARG}
+elif [ ${Option} = m ]; then
+	mode=${OPTARG}
+else
+	. /env/bin/_boot_help
+	exit 0
+fi
+done
+
+if [ x$mode = xnand ]; then
 	rootfs_loc=nand
 	kernel_loc=nand
-elif [ x$1 = xnor ]; then
+elif [ x$mode = xnor ]; then
 	rootfs_loc=nor
 	kernel_loc=nor
-elif [ x$1 = xnfs ]; then
+elif [ x$mode = xnfs ]; then
 	rootfs_loc=net
 	kernel_loc=nfs
-elif [ x$1 = xtftp ]; then
+elif [ x$mode = xtftp ]; then
 	rootfs_loc=net
 	kernel_loc=tftp
-elif [ x$1 = xdisk ]; then
+elif [ x$mode = xdisk ]; then
 	rootfs_loc=disk
 	kernel_loc=disk
 fi