diff --git a/ChangeLog b/ChangeLog
index 1159d32a5..96abe1229 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2011-10-19  Szymon Janc <szymon@janc.net.pl>
+
+	* grub-core/bus/usb/uhci.c (grub_uhci_setup_transfer): Fix possible
+	NULL pointer dereference.
+
 2011-10-19  Vladimir Serbinenko  <phcoder@gmail.com>
 
 	Removed unused GRUB_BOOT_VERSION. Check for kernel version is better
diff --git a/grub-core/bus/usb/uhci.c b/grub-core/bus/usb/uhci.c
index 260b7e876..a9a4c45a2 100644
--- a/grub-core/bus/usb/uhci.c
+++ b/grub-core/bus/usb/uhci.c
@@ -544,8 +544,11 @@ grub_uhci_setup_transfer (grub_usb_controller_t dev,
 	{
 	  grub_size_t actual = 0;
 	  /* Terminate and free.  */
-	  td_prev->linkptr2 = 0;
-	  td_prev->linkptr = 1;
+	  if (td_prev)
+	    {
+	      td_prev->linkptr2 = 0;
+	      td_prev->linkptr = 1;
+	    }
 
 	  if (cdata->td_first)
 	    grub_free_queue (u, cdata->qh, cdata->td_first, NULL, &actual);