diff -ru rockbox-19989-dma03/apps/buffering.c rockbox-19989-dev/apps/buffering.c
--- rockbox-19989-dma03/apps/buffering.c	2009-02-12 16:32:18.944600000 -0500
+++ rockbox-19989-dev/apps/buffering.c	2009-02-12 16:38:05.388600000 -0500
@@ -86,7 +86,11 @@
 /* default point to start buffer refill */
 #define BUFFERING_DEFAULT_WATERMARK      (1024*128)
 /* amount of data to read in one read() call */
+#if defined(HAVE_LBA48) && defined(HAVE_ATA_DMA)
+#define BUFFERING_DEFAULT_FILECHUNK      (2048*512) /* FIXME: For testing only */
+#else
 #define BUFFERING_DEFAULT_FILECHUNK      (1024*256) /* AB: enlarged to 256KB */
+#endif
 
 #define BUF_HANDLE_MASK                  0x7FFFFFFF
 
@@ -606,8 +610,12 @@
         size_t copy_n = MIN( MIN(h->filerem, BUFFERING_DEFAULT_FILECHUNK),
                              buffer_len - h->widx);
 
-        /* stop copying if it would overwrite the reading position */
-        if (RINGBUF_ADD_CROSS(h->widx, copy_n, buf_ridx) >= 0)
+        /* Don't overwrite the reading position */
+        if (buf_ridx >= h->widx)
+            copy_n = MIN(buf_ridx - h->widx, copy_n);
+
+        /* Check if buffer is full */
+        if (copy_n == 0)
             return false;
 
         /* This would read into the next handle, this is broken */
diff -ru rockbox-19989-dma03/firmware/drivers/ata.c rockbox-19989-dev/firmware/drivers/ata.c
--- rockbox-19989-dma03/firmware/drivers/ata.c	2009-02-12 16:32:11.754600000 -0500
+++ rockbox-19989-dev/firmware/drivers/ata.c	2009-02-12 15:45:53.056400000 -0500
@@ -1483,7 +1483,7 @@
 
 #ifdef HAVE_LBA48
         if (identify_info[83] & 0x0400       /* 48 bit address support */
-            && total_sectors == 0x0FFFFFFF)  /* and disk size >= 128 GiB */
+) //            && total_sectors == 0x0FFFFFFF)  /* and disk size >= 128 GiB */
         {                                    /* (needs BigLBA addressing) */
             if (identify_info[102] || identify_info[103])
                 panicf("Unsupported disk size: >= 2^32 sectors");
diff -ru rockbox-19989-dma03/firmware/drivers/fat.c rockbox-19989-dev/firmware/drivers/fat.c
--- rockbox-19989-dma03/firmware/drivers/fat.c	2008-12-24 13:34:52.590000000 -0500
+++ rockbox-19989-dev/firmware/drivers/fat.c	2009-02-12 16:08:05.787600000 -0500
@@ -2172,7 +2172,11 @@
             first = sector;
 
         if ( ((sector != first) && (sector != last+1)) || /* not sequential */
+#if defined(HAVE_LBA48) && defined(HAVE_ATA_DMA)
+             (last-first+1 == 2048) ) { /* Max 2048 sectors per pp502x DMA request */
+#else
              (last-first+1 == 256) ) { /* max 256 sectors per ata request */
+#endif
             long count = last - first + 1;
             rc = transfer(IF_MV2(fat_bpb,) first, count, buf, write );
             if (rc < 0)
diff -ru rockbox-19989-dma03/firmware/export/config-ipodvideo.h rockbox-19989-dev/firmware/export/config-ipodvideo.h
--- rockbox-19989-dma03/firmware/export/config-ipodvideo.h	2009-02-12 16:32:11.713600000 -0500
+++ rockbox-19989-dev/firmware/export/config-ipodvideo.h	2009-02-12 15:00:14.755400000 -0500
@@ -206,4 +206,7 @@
 
 /* Define this to add support for ATA DMA */
 #define HAVE_ATA_DMA
+
+/* Enable LBA48 for long reads */
+#define HAVE_LBA48
 #endif