diff --git a/pym/cl_fill.py b/pym/cl_fill.py
index 0f53c65..172b861 100644
--- a/pym/cl_fill.py
+++ b/pym/cl_fill.py
@@ -23,7 +23,8 @@ import cl_overriding
 from cl_vars_share import varsShare, clLocale
 from os.path import exists as pathexists
 from os import path
-from cl_utils import isMount, genpassword, getAvailableX11Drivers
+from cl_utils import isMount, genpassword, getAvailableX11Drivers, \
+                     listDirectory
 from encrypt import getHash
 
 class fillVars(varsShare):
@@ -206,80 +207,59 @@ class fillVars(varsShare):
 
     def get_os_root_dev(self):
         """Root filesystem device"""
-        for record in open('/proc/cmdline','rb').readlines():
-            re_res=re.search('(?:^|\s)root=(\S+)(\s|$)',record.strip())
-            if re_res:
-                rootparam=re_res.group(1)
-                # check root for /dev/sd view
-                if re.match("^\/dev\/[a-z]+[0-9]$",rootparam):
-                    return rootparam
-                # check root set by uuid
-                uuidpath = '/dev/disk/by-uuid'
-                if os.access(uuidpath,os.R_OK):
-                    uuidDevs = filter(path.islink,
-                                  map(lambda x: path.join(uuidpath,x),
-                                      os.listdir(uuidpath)))
-                    mapUuidDev = dict(map(lambda x:(path.basename(x),
-                                    path.normpath(path.join(uuidpath,
-                                    os.readlink(x)))), uuidDevs))
-                else:
-                    mapUuidDev = {}
-                if re.match("^UUID=.*$",rootparam):
-                    uuid = rootparam[5:]
-                    if uuid in mapUuidDev:
-                        return mapUuidDev[uuid]
-            mountLunes = self._runos("mount")
-            if not mountLunes:
-                return ""
-            if type(mountLunes) == types.ListType:
-                root_dev = mountLunes[0].split("on / type")[0].strip()
-                if root_dev:
-                    return root_dev
+        record = open('/proc/cmdline','rb').read().strip()
+        re_resRealRoot=re.search('(?:^|\s)real_root=(\S+)(\s|$)',record)
+        re_resFakeRoot=re.search('(?:^|\s)root=(\S+)(\s|$)',record)
+        # param real_root priority that root
+        re_res = re_resRealRoot or re_resFakeRoot
+        if re_res:
+            rootparam=re_res.group(1)
+            # check root for /dev/sd view
+            if re.match("^\/dev\/[a-z]+.*$", rootparam):
+                return rootparam
+            # check root set by uuid
+            uuidpath = '/dev/disk/by-uuid'
+            if os.access(uuidpath,os.R_OK):
+                uuidDevs = filter(path.islink,
+                              map(lambda x: path.join(uuidpath,x),
+                                  os.listdir(uuidpath)))
+                mapUuidDev = dict(map(lambda x:(path.basename(x),
+                                path.normpath(path.join(uuidpath,
+                                os.readlink(x)))), uuidDevs))
+            else:
+                mapUuidDev = {}
+            if re.match("^UUID=.*$",rootparam):
+                uuid = rootparam[5:]
+                if uuid in mapUuidDev:
+                    return mapUuidDev[uuid]
+        # get device mounted to root
+        dfLines = self._runos("LANG=C df /")
+        if not dfLines:
             return ""
+        if type(dfLines) == types.ListType and len(dfLines)>1:
+            root_dev = dfLines[1].split(" ")[0].strip()
+            if root_dev:
+                return {'none':'/dev/ram0'}.get(root_dev,root_dev)
+        return ""
 
     def get_os_root_type(self):
         """Root device type (ram, hdd, livecd)"""
-        mountLunes = self._runos("mount")
-        if not mountLunes:
-            return ""
-        rootType = "hdd"
-        if type(mountLunes) == types.ListType:
-            flagCD = False
-            for line in mountLunes:
-                if "/dev/loop0 on / type" in line:
-                    rootType = "ram"
-                    break
-                elif "/dev/loop0 on /newroot/mnt/livecd type" in line:
-                    rootType = "ram"
-                    flagCD = True
-                    break
-            if rootType == "ram":
-                if path.exists("/mnt/livecd") or flagCD:
-                    rootType = "livecd"
-                    return rootType
-            rootDev = self.Get("os_root_dev")
-            if rootType != "ram" and rootDev:
-                slpRootDev = rootDev.split("/dev/")
-                if len(slpRootDev) == 2:
-                    rDev = slpRootDev[1]
-                    if os.path.exists('/dev/disk/by-id'):
-                        devLines = os.listdir("/dev/disk/by-id")
-                        for name in devLines:
-                            pathname = path.join("/dev/disk/by-id", name)
-                            if path.islink(pathname):
-                                if rDev in os.readlink(pathname) and \
-                                    "usb-" in name:
-                                    rootType = "usb-hdd"
-                                    break
-                    else:
-                        devLines = None
-                    if not devLines:
-                        return ""
-            if rootType == "ram":
-                rootType = "hdd"
-            return rootType
-        else:
-            return ""
+        def link2pair(linkfile):
+            """Return pair (target,link) from link"""
+            basedir = os.path.dirname(linkfile)
+            targetfile = os.readlink(linkfile)
+            return (path.normpath(os.path.join(basedir,targetfile)),linkfile)
+        rootDev = self.Get("os_root_dev")
+        if rootDev:
+            if "/dev/ram" in rootDev:
+                return "livecd"
+            idDict = dict(map(link2pair,
+                     filter(lambda x:path.islink(x),
+                     map(lambda x:path.join('/dev/disk/by-id',x),
+                     listDirectory('/dev/disk/by-id')))))
+            if "usb-" in idDict.get(rootDev,""):
+                return "usb-hdd"
+        return "hdd"
 
     def get_hr_cdrom_set(self):
         """Cdrom variable"""