diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 9329f04b0907af62db87b4b77c96c1028e313d84..ab562853b89283f3b6bd769d5f9e382454f4f058 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -339,7 +339,9 @@ static void pc_xen_hvm_init(QEMUMachineInitArgs *args)
     .desc = "Standard PC (i440FX + PIIX, 1996)", \
     .hot_add_cpu = pc_hot_add_cpu
 
-#define PC_I440FX_2_0_MACHINE_OPTIONS PC_I440FX_MACHINE_OPTIONS
+#define PC_I440FX_2_0_MACHINE_OPTIONS                           \
+    PC_I440FX_MACHINE_OPTIONS,                                  \
+    .default_machine_opts = "firmware=bios-256k.bin"
 
 static QEMUMachine pc_i440fx_machine_v2_0 = {
     PC_I440FX_2_0_MACHINE_OPTIONS,
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index ac69e5d20b36fb74d9a1f7ae6711228c9f579429..97aa84264c1b023e2450a1d8e3776a3fb2c69f98 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -259,7 +259,9 @@ static void pc_q35_init_1_4(QEMUMachineInitArgs *args)
     .desc = "Standard PC (Q35 + ICH9, 2009)", \
     .hot_add_cpu = pc_hot_add_cpu
 
-#define PC_Q35_2_0_MACHINE_OPTIONS PC_Q35_MACHINE_OPTIONS
+#define PC_Q35_2_0_MACHINE_OPTIONS                      \
+    PC_Q35_MACHINE_OPTIONS,                             \
+    .default_machine_opts = "firmware=bios-256k.bin"
 
 static QEMUMachine pc_q35_machine_v2_0 = {
     PC_Q35_2_0_MACHINE_OPTIONS,