diff --git a/src/target/aarch64.c b/src/target/aarch64.c
index 30ef54792..d11fd943b 100644
--- a/src/target/aarch64.c
+++ b/src/target/aarch64.c
@@ -102,6 +102,7 @@ static int aarch64_restore_system_control_reg(struct target *target)
 		case ARM_MODE_FIQ:
 		case ARM_MODE_IRQ:
 		case ARM_MODE_HYP:
+		case ARM_MODE_UND:
 		case ARM_MODE_SYS:
 			instr = ARMV4_5_MCR(15, 0, 0, 1, 0, 0);
 			break;
@@ -180,6 +181,7 @@ static int aarch64_mmu_modify(struct target *target, int enable)
 	case ARM_MODE_FIQ:
 	case ARM_MODE_IRQ:
 	case ARM_MODE_HYP:
+	case ARM_MODE_UND:
 	case ARM_MODE_SYS:
 		instr = ARMV4_5_MCR(15, 0, 0, 1, 0, 0);
 		break;
@@ -1049,6 +1051,7 @@ static int aarch64_post_debug_entry(struct target *target)
 	case ARM_MODE_FIQ:
 	case ARM_MODE_IRQ:
 	case ARM_MODE_HYP:
+	case ARM_MODE_UND:
 	case ARM_MODE_SYS:
 		instr = ARMV4_5_MRC(15, 0, 0, 1, 0, 0);
 		break;
diff --git a/src/target/armv8.c b/src/target/armv8.c
index 26116bb33..2de115712 100644
--- a/src/target/armv8.c
+++ b/src/target/armv8.c
@@ -77,6 +77,10 @@ static const struct {
 		.name = "HYP",
 		.psr = ARM_MODE_HYP,
 	},
+	{
+		.name = "UND",
+		.psr = ARM_MODE_UND,
+	},
 	{
 		.name = "SYS",
 		.psr = ARM_MODE_SYS,