diff --git a/CHANGES b/CHANGES
index 866b6125c..35e65d7d4 100644
--- a/CHANGES
+++ b/CHANGES
@@ -39,6 +39,7 @@ Misc:
  - All: Add QUIET parameter to silence CMake
  - GBA Video: Null renderer should return proper register values
  - Libretro: Disable logging game errors, BIOS calls and stubs in release builds
+ - ARM7: Support forcing Thumb mode via MSR
 
 0.4.0: (2016-02-02)
 Features:
diff --git a/src/arm/isa-arm.c b/src/arm/isa-arm.c
index 518ab5134..bf826f44b 100644
--- a/src/arm/isa-arm.c
+++ b/src/arm/isa-arm.c
@@ -629,6 +629,9 @@ DEFINE_INSTRUCTION_ARM(MSR,
 	if (mask & PSR_USER_MASK) {
 		cpu->cpsr.packed = (cpu->cpsr.packed & ~PSR_USER_MASK) | (operand & PSR_USER_MASK);
 	}
+	if (mask & PSR_STATE_MASK) {
+		cpu->cpsr.packed = (cpu->cpsr.packed & ~PSR_STATE_MASK) | (operand & PSR_STATE_MASK);
+	}
 	if (cpu->privilegeMode != MODE_USER && (mask & PSR_PRIV_MASK)) {
 		ARMSetPrivilegeMode(cpu, (enum PrivilegeMode) ((operand & 0x0000000F) | 0x00000010));
 		cpu->cpsr.packed = (cpu->cpsr.packed & ~PSR_PRIV_MASK) | (operand & PSR_PRIV_MASK);
diff --git a/src/arm/isa-inlines.h b/src/arm/isa-inlines.h
index 42a581b4a..2e7395a00 100644
--- a/src/arm/isa-inlines.h
+++ b/src/arm/isa-inlines.h
@@ -85,6 +85,8 @@ static inline void _ARMSetMode(struct ARMCore* cpu, enum ExecutionMode execution
 		break;
 	case MODE_THUMB:
 		cpu->cpsr.t = 1;
+		cpu->prefetch[0] &= 0xFFFF;
+		cpu->prefetch[1] &= 0xFFFF;
 	}
 	cpu->nextEvent = cpu->cycles;
 }