diff --git a/drivers/acpi/acpica/tbfadt.c b/drivers/acpi/acpica/tbfadt.c
index c5d870406f41..4c9c760db4a4 100644
--- a/drivers/acpi/acpica/tbfadt.c
+++ b/drivers/acpi/acpica/tbfadt.c
@@ -363,10 +363,6 @@ static void acpi_tb_convert_fadt(void)
 	u32 address32;
 	u32 i;
 
-	/* Update the local FADT table header length */
-
-	acpi_gbl_FADT.header.length = sizeof(struct acpi_table_fadt);
-
 	/*
 	 * Expand the 32-bit FACS and DSDT addresses to 64-bit as necessary.
 	 * Later code will always use the X 64-bit field. Also, check for an
@@ -408,6 +404,10 @@ static void acpi_tb_convert_fadt(void)
 		acpi_gbl_FADT.boot_flags = 0;
 	}
 
+	/* Update the local FADT table header length */
+
+	acpi_gbl_FADT.header.length = sizeof(struct acpi_table_fadt);
+
 	/*
 	 * Expand the ACPI 1.0 32-bit addresses to the ACPI 2.0 64-bit "X"
 	 * generic address structures as necessary. Later code will always use