diff --git a/Makefile b/Makefile
index b9d26d2a5..42186ce22 100644
--- a/Makefile
+++ b/Makefile
@@ -116,6 +116,7 @@ CFLAGS = -DVERSION=$(VERSION) \
 	-woff 581,649,819,820,821,838,852 \
 	-w2 \
 	-I src/include \
+	$(OPT_LVL) \
 	$(MIPSISET)
 
 C_FILES := $(shell find src/gvars src/boot src/lib src/game src/inflate src/mpconfigs src/mpstrings/$(ROMID) src/firingrange src/filenames src/textureconfig -name '*.c')
@@ -332,7 +333,7 @@ $(B_DIR)/files/G%Z: $(E_DIR)/files/G%Z
 # Lang
 $(B_DIR)/files/lang/L%.o: src/files/lang/$(ROMID)/%.c
 	@mkdir -p $(B_DIR)/files/lang
-	$(IDOCC) -c $(CFLAGS) $< -o $@ $(OPT_LVL)
+	$(IDOCC) -c $(CFLAGS) $< -o $@
 
 $(B_DIR)/files/L%.elf: $(B_DIR)/files/lang/L%.o
 	TOOLCHAIN=$(TOOLCHAIN) tools/mksimpleelf $< $@
@@ -394,37 +395,37 @@ $(B_DIR)/copyright.o: $(B_DIR)/copyright.bin
 
 $(B_DIR)/boot/%.o: src/boot/%.c
 	@mkdir -p $(dir $@)
-	/usr/bin/env python3 tools/asmpreproc/asm-processor.py -O2 $< | $(IDOCC) -c $(CFLAGS) tools/asmpreproc/include-stdin.c -o $@ $(OPT_LVL)
+	/usr/bin/env python3 tools/asmpreproc/asm-processor.py -O2 $< | $(IDOCC) -c $(CFLAGS) tools/asmpreproc/include-stdin.c -o $@
 	/usr/bin/env python3 tools/asmpreproc/asm-processor.py -O2 $< --post-process $@ --assembler "$(TOOLCHAIN)-as -march=vr4300 -mabi=32" --asm-prelude tools/asmpreproc/prelude.s
 
 $(B_DIR)/lib/ultra/libc/llcvt.o: src/lib/ultra/libc/llcvt.c
 	@mkdir -p $(dir $@)
-	/usr/bin/env python3 tools/asmpreproc/asm-processor.py -O2 $< | $(IDOCC) -c $(CFLAGS) tools/asmpreproc/include-stdin.c -o $@ $(OPT_LVL)
+	/usr/bin/env python3 tools/asmpreproc/asm-processor.py -O2 $< | $(IDOCC) -c $(CFLAGS) tools/asmpreproc/include-stdin.c -o $@
 	/usr/bin/env python3 tools/asmpreproc/asm-processor.py -O2 $< --post-process $@ --assembler "$(TOOLCHAIN)-as -march=vr4300 -mabi=32" --asm-prelude tools/asmpreproc/prelude.s
 	tools/patchmips3 $@ || rm $@
 
 $(B_DIR)/lib/ultra/libc/ll.o: src/lib/ultra/libc/ll.c
 	@mkdir -p $(dir $@)
-	$(IDOCC) -c $(CFLAGS) $< -o $@ $(OPT_LVL)
+	$(IDOCC) -c $(CFLAGS) $< -o $@
 	tools/patchmips3 $@ || rm $@
 
 $(B_DIR)/lib/%.o: src/lib/%.c
 	@mkdir -p $(dir $@)
-	/usr/bin/env python3 tools/asmpreproc/asm-processor.py -O2 $< | $(IDOCC) -c $(CFLAGS) tools/asmpreproc/include-stdin.c -o $@ $(OPT_LVL)
+	/usr/bin/env python3 tools/asmpreproc/asm-processor.py -O2 $< | $(IDOCC) -c $(CFLAGS) tools/asmpreproc/include-stdin.c -o $@
 	/usr/bin/env python3 tools/asmpreproc/asm-processor.py -O2 $< --post-process $@ --assembler "$(TOOLCHAIN)-as -march=vr4300 -mabi=32" --asm-prelude tools/asmpreproc/prelude.s
 
 $(B_DIR)/game/%.o: src/game/%.c
 	@mkdir -p $(dir $@)
-	/usr/bin/env python3 tools/asmpreproc/asm-processor.py -O2 $< | $(IDOCC) -c $(CFLAGS) tools/asmpreproc/include-stdin.c -o $@ $(OPT_LVL)
+	/usr/bin/env python3 tools/asmpreproc/asm-processor.py -O2 $< | $(IDOCC) -c $(CFLAGS) tools/asmpreproc/include-stdin.c -o $@
 	/usr/bin/env python3 tools/asmpreproc/asm-processor.py -O2 $< --post-process $@ --assembler "$(TOOLCHAIN)-as -march=vr4300 -mabi=32" --asm-prelude tools/asmpreproc/prelude.s
 
 $(B_DIR)/%.o: src/%.c
 	@mkdir -p $(dir $@)
-	$(IDOCC) -c $(CFLAGS) $< -o $@ $(OPT_LVL)
+	$(IDOCC) -c $(CFLAGS) $< -o $@
 
 $(B_DIR)/%.o: src/%.s
 	@mkdir -p $(dir $@)
-	$(IDOAS) $(CFLAGS) $< -o $@ $(OPT_LVL)
+	$(IDOAS) $(CFLAGS) $< -o $@
 
 extract:
 	ROMID=$(ROMID) tools/extract
diff --git a/src/include/PR/os_libc.h b/src/include/PR/os_libc.h
index 9e47c45c0..5418a4820 100644
--- a/src/include/PR/os_libc.h
+++ b/src/include/PR/os_libc.h
@@ -21,7 +21,7 @@
 
 /*---------------------------------------------------------------------*
         Copyright (C) 1998 Nintendo. (Originated by SGI)
-        
+
         $RCSfile: os_libc.h,v $
         $Revision: 1.3 $
         $Date: 1999/07/13 01:43:47 $
diff --git a/src/include/PR/os_misc.h b/src/include/PR/os_misc.h
index b6755f370..cddbf366e 100644
--- a/src/include/PR/os_misc.h
+++ b/src/include/PR/os_misc.h
@@ -63,6 +63,36 @@ typedef struct {
     /* 34 */ char length;
 } printf_struct;
 
+typedef char *va_list;
+
+#define _FP 1
+#define _INT 0
+#define _STRUCT 2
+
+#define _VA_FP_SAVE_AREA 0x10
+#define _VA_ALIGN(p, a) (((unsigned int)(((char *)p) + ((a) > 4 ? (a) : 4) - 1)) & -((a) > 4 ? (a) : 4))
+#define va_start(vp, parmN) (vp = ((va_list)&parmN + sizeof(parmN)))
+
+#define __va_stack_arg(list, mode)                                 \
+  (                                                                \
+      ((list) = (char *)_VA_ALIGN(list, __builtin_alignof(mode)) + \
+                _VA_ALIGN(sizeof(mode), 4)),                       \
+      (((char *)list) - (_VA_ALIGN(sizeof(mode), 4) - sizeof(mode))))
+
+#define __va_double_arg(list, mode)                                                                  \
+  (                                                                                                  \
+      (((long)list & 0x1) /* 1 byte aligned? */                                                      \
+           ? (list = (char *)((long)list + 7), (char *)((long)list - 6 - _VA_FP_SAVE_AREA))          \
+           : (((long)list & 0x2) /* 2 byte aligned? */                                               \
+                  ? (list = (char *)((long)list + 10), (char *)((long)list - 24 - _VA_FP_SAVE_AREA)) \
+                  : __va_stack_arg(list, mode))))
+
+#define va_arg(list, mode) ((mode *)(((__builtin_classof(mode) == _FP &&          \
+                                       __builtin_alignof(mode) == sizeof(double)) \
+                                          ? __va_double_arg(list, mode)           \
+                                          : __va_stack_arg(list, mode))))[-1]
+#define va_end(__list)
+
 /* Miscellaneous OS functions */
 
 void osInitialize(void);
diff --git a/src/lib/ultra/libc/sprintf.c b/src/lib/ultra/libc/sprintf.c
index 956188ca8..88c42906e 100644
--- a/src/lib/ultra/libc/sprintf.c
+++ b/src/lib/ultra/libc/sprintf.c
@@ -32,3 +32,21 @@ glabel sprintf
 /*    13708:	00000000 */ 	nop
 /*    1370c:	00000000 */ 	nop
 );
+
+// Mismatch:
+// Goal takes v0 from _Printf and copies it to v1 but leaves v0 unmodified.
+// The below copies v0 to v1 then back to v0 for the return.
+//int sprintf(char *dst, const char *fmt, ...)
+//{
+//	int ans;
+//	va_list ap;
+//
+//	va_start(ap, fmt);
+//	ans = _Printf(proutSprintf, dst, fmt, ap);
+//
+//	if (ans >= 0) {
+//		dst[ans] = 0;
+//	}
+//
+//	return ans;
+//}