diff --git a/drivers/ieee1394/ohci1394.c b/drivers/ieee1394/ohci1394.c
index 1922287..11f1377 100644
--- a/drivers/ieee1394/ohci1394.c
+++ b/drivers/ieee1394/ohci1394.c
@@ -553,7 +553,7 @@
 	 * register content.
 	 * To actually enable physical responses is the job of our interrupt
 	 * handler which programs the physical request filter. */
-	reg_write(ohci, OHCI1394_PhyUpperBound, 0xffff0000);
+	reg_write(ohci, OHCI1394_PhyUpperBound, 0x01000000);
 
 	DBGMSG("physUpperBoundOffset=%08x",
 	       reg_read(ohci, OHCI1394_PhyUpperBound));
diff --git a/drivers/ieee1394/sbp2.c b/drivers/ieee1394/sbp2.c
index 7355580..8a23fb5 100644
--- a/drivers/ieee1394/sbp2.c
+++ b/drivers/ieee1394/sbp2.c
@@ -835,11 +835,16 @@
 
 	/* Register the status FIFO address range. We could use the same FIFO
 	 * for targets at different nodes. However we need different FIFOs per
-	 * target in order to support multi-unit devices. */
+	 * target in order to support multi-unit devices.
+	 * The FIFO is located out of the local host controller's physical range
+	 * but, if possible, within the posted write area. Status writes will
+	 * then be performed as unified transactions. This slightly reduces
+	 * bandwidth usage, and some Prolific based devices seem to require it.
+	 */
 	scsi_id->status_fifo_addr = hpsb_allocate_and_register_addrspace(
 			&sbp2_highlevel, ud->ne->host, &sbp2_ops,
 			sizeof(struct sbp2_status_block), sizeof(quadlet_t),
-			~0ULL, ~0ULL);
+			0x010000000000ULL, CSR1212_ALL_SPACE_END);
 	if (!scsi_id->status_fifo_addr) {
 		SBP2_ERR("failed to allocate status FIFO address range");
 		goto failed_alloc;