diff --git a/core/cfs/cfs-eeprom.c b/core/cfs/cfs-eeprom.c
index be3cc7675..1203bd951 100644
--- a/core/cfs/cfs-eeprom.c
+++ b/core/cfs/cfs-eeprom.c
@@ -30,7 +30,7 @@
  *
  * Author: Adam Dunkels <adam@sics.se>
  *
- * $Id: cfs-eeprom.c,v 1.4 2007/11/22 11:29:13 oliverschmidt Exp $
+ * $Id: cfs-eeprom.c,v 1.5 2008/01/08 14:27:06 adamdunkels Exp $
  */
 
 #include "cfs/cfs.h"
@@ -57,7 +57,17 @@ cfs_open(const char *n, int f)
 {
   if(file.flag == FLAG_FILE_CLOSED) {
     file.flag = FLAG_FILE_OPEN;
-    file.fileptr = 0;
+    if(f & CFS_READ) {
+      file.fileptr = 0;
+    }
+    if(f & CFS_WRITE){
+      if(f & CFS_APPEND) {
+	file.fileptr = file.filesize;
+      } else {
+	file.fileptr = 0;
+	file.filesize = 0;
+      }
+    }
     return 1;
   } else {
     return -1;
diff --git a/core/cfs/cfs-posix.c b/core/cfs/cfs-posix.c
index d0a6ae850..bd4310ae0 100644
--- a/core/cfs/cfs-posix.c
+++ b/core/cfs/cfs-posix.c
@@ -30,7 +30,7 @@
  *
  * Author: Adam Dunkels <adam@sics.se>
  *
- * $Id: cfs-posix.c,v 1.8 2007/12/23 14:12:44 oliverschmidt Exp $
+ * $Id: cfs-posix.c,v 1.9 2008/01/08 14:27:06 adamdunkels Exp $
  */
 
 #include <stdio.h>
@@ -43,7 +43,23 @@
 int
 cfs_open(const char *n, int f)
 {
-  return open(n, f == CFS_READ? O_RDONLY: O_CREAT|O_TRUNC|O_RDWR);
+  int s = 0;
+  if(f == CFS_READ) {
+    s = O_RDONLY;
+  } else if(f & CFS_WRITE) {
+    s = O_CREAT;
+    if(f & CFS_READ) {
+      s |= O_RDWR;
+    } else {
+      s |= O_WRONLY;
+    }
+    if(f & CFS_APPEND) {
+      s |= O_APPEND;
+    } else {
+      s |= O_TRUNC;
+    }
+  }
+  return open(n, s);
 }
 /*---------------------------------------------------------------------------*/
 void
diff --git a/core/cfs/cfs-ram.c b/core/cfs/cfs-ram.c
index 6d14bff1f..50a614cb6 100644
--- a/core/cfs/cfs-ram.c
+++ b/core/cfs/cfs-ram.c
@@ -30,7 +30,7 @@
  *
  * Author: Adam Dunkels <adam@sics.se>
  *
- * $Id: cfs-ram.c,v 1.5 2007/11/22 11:29:13 oliverschmidt Exp $
+ * $Id: cfs-ram.c,v 1.6 2008/01/08 14:27:06 adamdunkels Exp $
  */
 
 #include <string.h>
@@ -60,9 +60,16 @@ cfs_open(const char *n, int f)
 {
   if(file.flag == FLAG_FILE_CLOSED) {
     file.flag = FLAG_FILE_OPEN;
-    file.fileptr = 0;
-    if((f & CFS_WRITE) && !(f & CFS_APPEND)) {
-      file.filesize = 0;
+    if(f & CFS_READ) {
+      file.fileptr = 0;
+    }
+    if(f & CFS_WRITE){
+      if(f & CFS_APPEND) {
+	file.fileptr = file.filesize;
+      } else {
+	file.fileptr = 0;
+	file.filesize = 0;
+      }
     }
     return 1;
   } else {
@@ -79,6 +86,8 @@ cfs_close(int f)
 int
 cfs_read(int f, void *buf, unsigned int len)
 {
+  printf("read file.fileptr %d len %d filesize %d\n",
+	 file.fileptr, len, file.filesize);
   if(file.fileptr + len > sizeof(filemem)) {
     len = sizeof(filemem) - file.fileptr;
   }
@@ -99,6 +108,9 @@ cfs_read(int f, void *buf, unsigned int len)
 int
 cfs_write(int f, void *buf, unsigned int len)
 {
+  printf("write file.fileptr %d len %d filesize %d\n",
+	 file.fileptr, len, file.filesize);
+
   if(file.fileptr >= sizeof(filemem)) {
     return 0;
   }
diff --git a/core/cfs/cfs-xmem.c b/core/cfs/cfs-xmem.c
index d2216187d..9d4acb3bf 100644
--- a/core/cfs/cfs-xmem.c
+++ b/core/cfs/cfs-xmem.c
@@ -30,7 +30,7 @@
  *
  * Author: Adam Dunkels <adam@sics.se>
  *
- * $Id: cfs-xmem.c,v 1.6 2007/11/22 11:29:13 oliverschmidt Exp $
+ * $Id: cfs-xmem.c,v 1.7 2008/01/08 14:27:06 adamdunkels Exp $
  */
 
 #include "cfs/cfs.h"
@@ -65,10 +65,17 @@ cfs_open(const char *n, int f)
 {
   if(file.flag == FLAG_FILE_CLOSED) {
     file.flag = FLAG_FILE_OPEN;
-    file.fileptr = 0;
-    if((f & CFS_WRITE) && !(f & CFS_APPEND)) {
-      file.filesize = 0;
-      xmem_erase(CFS_XMEM_SIZE, CFS_XMEM_OFFSET);
+    if(f & CFS_READ) {
+      file.fileptr = 0;
+    }
+    if(f & CFS_WRITE){
+      if(f & CFS_APPEND) {
+	file.fileptr = file.filesize;
+      } else {
+	file.fileptr = 0;
+	file.filesize = 0;
+	xmem_erase(CFS_XMEM_SIZE, CFS_XMEM_OFFSET);
+      }
     }
     return 1;
   } else {
diff --git a/core/cfs/cfs.h b/core/cfs/cfs.h
index d44689183..f852785c6 100644
--- a/core/cfs/cfs.h
+++ b/core/cfs/cfs.h
@@ -54,7 +54,7 @@
  *
  * Author: Adam Dunkels <adam@sics.se>
  *
- * $Id: cfs.h,v 1.9 2007/12/23 15:22:33 oliverschmidt Exp $
+ * $Id: cfs.h,v 1.10 2008/01/08 14:27:06 adamdunkels Exp $
  */
 #ifndef __CFS_H__
 #define __CFS_H__
@@ -115,7 +115,7 @@ struct cfs_dirent {
 /**
  * \brief      Open a file.
  * \param name The name of the file.
- * \param flags CFS_READ, or CFS_WRITE, or both.
+ * \param flags CFS_READ, or CFS_WRITE/CFS_APPEND, or both.
  * \return     A file descriptor, if the file could be opened, or -1 if
  *             the file could not be opened.
  *