Index: firmware/usbstack/usb_storage.c
===================================================================
--- firmware/usbstack/usb_storage.c	(revision 20080)
+++ firmware/usbstack/usb_storage.c	(working copy)
@@ -283,6 +283,26 @@
     SENDING_CSW
 } state = WAITING_FOR_COMMAND;
 
+#ifdef TOSHIBA_GIGABEAT_S
+
+/* The Gigabeat S factory partition table contains invalid values for the
+   "active" flag in the MBR.  This prevents at least the Linux kernel from
+   accepting the partition table, so we fix it on-the-fly. */
+
+static void validate_mbr(unsigned char* mbr)
+{
+    int i;
+    unsigned char* p;
+
+    for (i = 0; i < 4 ; i++)
+    {
+        p = mbr + 0x1be + i*0x10;
+        if ((*p != 0) && (*p != 0x80))
+            *p = 0;
+    }
+}
+#endif
+
 static bool check_disk_present(IF_MV_NONVOID(int volume))
 {
 #ifdef USB_USE_RAMDISK
@@ -985,7 +1005,13 @@
                                              MIN(BUFFER_SIZE/SECTOR_SIZE,
                                                  cur_cmd.count),
                                              cur_cmd.data[cur_cmd.data_select]);
+
+#ifdef TOSHIBA_GIGABEAT_S
+                if (cur_cmd.sector == 0) {
+                    validate_mbr(cur_cmd.data[cur_cmd.data_select]);
+                }
 #endif
+#endif
                 send_and_read_next();
             }
             break;