diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
index 8b6806a79edf..cc618f8beb3f 100644
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -16248,6 +16248,65 @@ static bool tg3_10_100_only_device(struct tg3 *tp,
 	return false;
 }
 
+static int tg3_fw_byteorder(struct tg3 *tp, u32 *misc_ctrl_reg)
+{
+	struct pci_dev *pdev = tp->pdev;
+	u32 prodid, expected_prodid, normalized, readback;
+	int reg, err;
+
+	/* Prefer the normal revision marker before testing the swapped state. */
+	if (pdev->device != TG3PCI_DEVICE_TIGON3_5718 ||
+	    (*misc_ctrl_reg >> 28) == ASIC_REV_USE_PROD_ID_REG ||
+	    (swab32(*misc_ctrl_reg) >> 28) != ASIC_REV_USE_PROD_ID_REG ||
+	    !(swab32(*misc_ctrl_reg) & MISC_HOST_CTRL_BYTE_SWAP))
+		return 0;
+
+	/* Standard PCI fields are normal; verify the swapped vendor registers. */
+	reg = TG3PCI_GEN2_PRODID_ASICREV;
+	err = pci_read_config_dword(pdev, reg, &prodid);
+	if (err)
+		goto config_error;
+	expected_prodid = swab32(prodid);
+	if ((expected_prodid >> 12) != ASIC_REV_5717) {
+		dev_err(&pdev->dev, "unexpected swapped BCM5718 product ID %08x\n",
+			prodid);
+		return -ENODEV;
+	}
+
+	normalized = (swab32(*misc_ctrl_reg) & MISC_HOST_CTRL_CHIPREV) |
+		     tp->misc_host_ctrl;
+	reg = TG3PCI_MISC_HOST_CTRL;
+	err = pci_write_config_dword(pdev, reg, swab32(normalized));
+	if (err)
+		goto config_error;
+	err = pci_read_config_dword(pdev, reg, &readback);
+	if (err)
+		goto config_error;
+	if (readback != normalized) {
+		dev_err(&pdev->dev, "BCM5718 host-control readback mismatch %08x\n",
+			readback);
+		return -EIO;
+	}
+
+	reg = TG3PCI_GEN2_PRODID_ASICREV;
+	err = pci_read_config_dword(pdev, reg, &prodid);
+	if (err)
+		goto config_error;
+	if (prodid != expected_prodid) {
+		dev_err(&pdev->dev, "BCM5718 product-ID readback mismatch %08x\n",
+			prodid);
+		return -EIO;
+	}
+	*misc_ctrl_reg = readback;
+	dev_dbg(&pdev->dev, "normalized firmware register byte order\n");
+	return 0;
+
+config_error:
+	dev_err(&pdev->dev, "BCM5718 PCI config access at %#x failed (%d)\n",
+		reg, err);
+	return pcibios_err_to_errno(err);
+}
+
 static int tg3_get_invariants(struct tg3 *tp, const struct pci_device_id *ent)
 {
 	u32 misc_ctrl_reg;
@@ -16272,8 +16331,17 @@ static int tg3_get_invariants(struct tg3 *tp, const struct pci_device_id *ent)
 	 * sure that indirect register accesses are enabled before
 	 * the first operation.
 	 */
-	pci_read_config_dword(tp->pdev, TG3PCI_MISC_HOST_CTRL,
-			      &misc_ctrl_reg);
+	err = pci_read_config_dword(tp->pdev, TG3PCI_MISC_HOST_CTRL,
+				    &misc_ctrl_reg);
+	if (err && tp->pdev->device == TG3PCI_DEVICE_TIGON3_5718) {
+		dev_err(&tp->pdev->dev, "PCI host-control read failed (%d)\n",
+			err);
+		return pcibios_err_to_errno(err);
+	}
+	err = tg3_fw_byteorder(tp, &misc_ctrl_reg);
+	if (err)
+		return err;
+
 	tp->misc_host_ctrl |= (misc_ctrl_reg &
 			       MISC_HOST_CTRL_CHIPREV);
 	pci_write_config_dword(tp->pdev, TG3PCI_MISC_HOST_CTRL,