diff --git a/src/gb/gb.c b/src/gb/gb.c
index 377df10cb..b87e793d3 100644
--- a/src/gb/gb.c
+++ b/src/gb/gb.c
@@ -25,6 +25,7 @@ static void GBInit(struct LR35902Core* cpu, struct LR35902Component* component);
 static void GBInterruptHandlerInit(struct LR35902InterruptHandler* irqh);
 static void GBProcessEvents(struct LR35902Core* cpu);
 static void GBSetInterrupts(struct LR35902Core* cpu, bool enable);
+static void GBIllegal(struct LR35902Core* cpu);
 static void GBHitStub(struct LR35902Core* cpu);
 
 void GBCreate(struct GB* gb) {
@@ -124,6 +125,7 @@ void GBInterruptHandlerInit(struct LR35902InterruptHandler* irqh) {
 	irqh->reset = GBReset;
 	irqh->processEvents = GBProcessEvents;
 	irqh->setInterrupts = GBSetInterrupts;
+	irqh->hitIllegal = GBIllegal;
 	irqh->hitStub = GBHitStub;
 	irqh->halt = GBHalt;
 }
@@ -231,6 +233,11 @@ void GBHalt(struct LR35902Core* cpu) {
 	cpu->halted = true;
 }
 
+void GBIllegal(struct LR35902Core* cpu) {
+	// TODO
+	mLOG(GB, GAME_ERROR, "Hit illegal opcode at address %04X:%02X\n", cpu->pc, cpu->bus);
+}
+
 void GBHitStub(struct LR35902Core* cpu) {
 	// TODO
 	mLOG(GB, STUB, "Hit stub at address %04X:%02X\n", cpu->pc, cpu->bus);
diff --git a/src/lr35902/emitter-lr35902.h b/src/lr35902/emitter-lr35902.h
index ff25b9343..07f68ba73 100644
--- a/src/lr35902/emitter-lr35902.h
+++ b/src/lr35902/emitter-lr35902.h
@@ -221,7 +221,7 @@
 	DECLARE_INSTRUCTION_LR35902(EMITTER, RETNC), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, POPDE), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, JPNC), \
-	DECLARE_INSTRUCTION_LR35902(EMITTER, STUB), \
+	DECLARE_INSTRUCTION_LR35902(EMITTER, ILL), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, CALLNC), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, PUSHDE), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, SUB), \
@@ -229,32 +229,32 @@
 	DECLARE_INSTRUCTION_LR35902(EMITTER, RETC), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, RETI), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, JPC), \
-	DECLARE_INSTRUCTION_LR35902(EMITTER, STUB), \
+	DECLARE_INSTRUCTION_LR35902(EMITTER, ILL), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, CALLC), \
-	DECLARE_INSTRUCTION_LR35902(EMITTER, STUB), \
+	DECLARE_INSTRUCTION_LR35902(EMITTER, ILL), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, SBC), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, RST18), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, LDIOA), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, POPHL), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, LDIOCA), \
-	DECLARE_INSTRUCTION_LR35902(EMITTER, STUB), \
-	DECLARE_INSTRUCTION_LR35902(EMITTER, STUB), \
+	DECLARE_INSTRUCTION_LR35902(EMITTER, ILL), \
+	DECLARE_INSTRUCTION_LR35902(EMITTER, ILL), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, PUSHHL), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, AND), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, RST20), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, ADDSP), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, JPHL), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, LDIA), \
-	DECLARE_INSTRUCTION_LR35902(EMITTER, STUB), \
-	DECLARE_INSTRUCTION_LR35902(EMITTER, STUB), \
-	DECLARE_INSTRUCTION_LR35902(EMITTER, STUB), \
+	DECLARE_INSTRUCTION_LR35902(EMITTER, ILL), \
+	DECLARE_INSTRUCTION_LR35902(EMITTER, ILL), \
+	DECLARE_INSTRUCTION_LR35902(EMITTER, ILL), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, XOR), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, RST28), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, LDAIO), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, POPAF), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, LDAIOC), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, DI), \
-	DECLARE_INSTRUCTION_LR35902(EMITTER, STUB), \
+	DECLARE_INSTRUCTION_LR35902(EMITTER, ILL), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, PUSHAF), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, OR), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, RST30), \
@@ -262,8 +262,8 @@
 	DECLARE_INSTRUCTION_LR35902(EMITTER, LDSP_HL), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, LDAI), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, EI), \
-	DECLARE_INSTRUCTION_LR35902(EMITTER, STUB), \
-	DECLARE_INSTRUCTION_LR35902(EMITTER, STUB), \
+	DECLARE_INSTRUCTION_LR35902(EMITTER, ILL), \
+	DECLARE_INSTRUCTION_LR35902(EMITTER, ILL), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, CP), \
 	DECLARE_INSTRUCTION_LR35902(EMITTER, RST38)
 
diff --git a/src/lr35902/isa-lr35902.c b/src/lr35902/isa-lr35902.c
index 79548f284..15b2d8ec1 100644
--- a/src/lr35902/isa-lr35902.c
+++ b/src/lr35902/isa-lr35902.c
@@ -757,6 +757,7 @@ DEFINE_RST_INSTRUCTION_LR35902(28);
 DEFINE_RST_INSTRUCTION_LR35902(30);
 DEFINE_RST_INSTRUCTION_LR35902(38);
 
+DEFINE_INSTRUCTION_LR35902(ILL, cpu->irqh.hitIllegal(cpu));
 DEFINE_INSTRUCTION_LR35902(STUB, cpu->irqh.hitStub(cpu));
 
 static const LR35902Instruction _lr35902CBInstructionTable[0x100] = {
diff --git a/src/lr35902/lr35902.h b/src/lr35902/lr35902.h
index ba95ed542..3b1ed0e7f 100644
--- a/src/lr35902/lr35902.h
+++ b/src/lr35902/lr35902.h
@@ -62,6 +62,7 @@ struct LR35902InterruptHandler {
 	void (*setInterrupts)(struct LR35902Core* cpu, bool enable);
 	void (*halt)(struct LR35902Core* cpu);
 
+	void (*hitIllegal)(struct LR35902Core* cpu);
 	void (*hitStub)(struct LR35902Core* cpu);
 };