diff --git a/oscar64/NativeCodeGenerator.cpp b/oscar64/NativeCodeGenerator.cpp
index ee43e9e..55a1af6 100644
--- a/oscar64/NativeCodeGenerator.cpp
+++ b/oscar64/NativeCodeGenerator.cpp
@@ -23835,7 +23835,7 @@ bool NativeCodeBasicBlock::JoinTailCodeSequences(NativeCodeProcedure* proc, bool
 					mTrueJump->mIns.Remove(0);
 					mTrueJump->mEntryRequiredRegs += CPU_REG_A;
 
-					if (mTrueJump->mIns[0].mLive & LIVE_CPU_REG_Z)
+					if (mTrueJump->mIns.Size() > 0 && (mTrueJump->mIns[0].mLive & LIVE_CPU_REG_Z))
 						mTrueJump->mEntryRequiredRegs += CPU_REG_Z;
 
 					changed = true;
diff --git a/oscar64/oscar64.cpp b/oscar64/oscar64.cpp
index 1721938..5b0c32d 100644
--- a/oscar64/oscar64.cpp
+++ b/oscar64/oscar64.cpp
@@ -253,7 +253,7 @@ int main2(int argc, const char** argv)
 				{
 					defining = true;
 				}
-				else if (arg[1] == 'd')
+				else if (arg[1] == 'd' || arg[1] == 'D')
 				{
 					char	def[100];
 					int i = 2;