diff --git a/sys/dev/bge/if_bge.c b/sys/dev/bge/if_bge.c
index 139df3d0855..95de34cb0bb 100644
--- a/sys/dev/bge/if_bge.c
+++ b/sys/dev/bge/if_bge.c
@@ -1693,6 +1693,11 @@ bge_blockinit(struct bge_softc *sc)
 		bge_writembx(sc, BGE_MBX_RX_MINI_PROD_LO, 0);
 	}
 
+	/* Choose de-pipeline mode for BCM5906 A1. */
+	if (sc->bge_asicrev == BGE_ASICREV_BCM5906 &&
+	    sc->bge_chiprev == BGE_CHIPID_BCM5906_A1)
+		CSR_WRITE_4(sc, BGE_ISO_PKT_TX,
+		    (CSR_READ_4(sc, BGE_ISO_PKT_TX) & ~3) | 2);
 	/*
 	 * The BD ring replenish thresholds control how often the
 	 * hardware fetches new BD's from the producer rings in host
diff --git a/sys/dev/bge/if_bgereg.h b/sys/dev/bge/if_bgereg.h
index 8211df183c8..a4f3f834b61 100644
--- a/sys/dev/bge/if_bgereg.h
+++ b/sys/dev/bge/if_bgereg.h
@@ -880,6 +880,7 @@
 #define	BGE_SDI_STATS_CTL		0x0C08
 #define	BGE_SDI_STATS_ENABLE_MASK	0x0C0C
 #define	BGE_SDI_STATS_INCREMENT_MASK	0x0C10
+#define	BGE_ISO_PKT_TX			0x0C20
 #define	BGE_LOCSTATS_COS0		0x0C80
 #define	BGE_LOCSTATS_COS1		0x0C84
 #define	BGE_LOCSTATS_COS2		0x0C88