diff --git a/release/files_common b/release/files_common
index f304f8526a..ec54ac1ac5 100644
--- a/release/files_common
+++ b/release/files_common
@@ -391,7 +391,7 @@ selfdrive/modeld/constants.py
 selfdrive/modeld/modeld
 selfdrive/modeld/dmonitoringmodeld
 
-selfdrive/modeld/models/commonmodel.cc
+selfdrive/modeld/models/commonmodel.c
 selfdrive/modeld/models/commonmodel.h
 selfdrive/modeld/models/driving.cc
 selfdrive/modeld/models/driving.h
@@ -400,8 +400,7 @@ selfdrive/modeld/models/dmonitoring.h
 
 selfdrive/modeld/transforms/loadyuv.[c,h]
 selfdrive/modeld/transforms/loadyuv.cl
-selfdrive/modeld/transforms/transform.cc
-selfdrive/modeld/transforms/transform.h
+selfdrive/modeld/transforms/transform.[c,h]
 selfdrive/modeld/transforms/transform.cl
 
 selfdrive/modeld/thneed/thneed.*
diff --git a/selfdrive/common/mat.h b/selfdrive/common/mat.h
index 626f3404fe..1c20eae17f 100644
--- a/selfdrive/common/mat.h
+++ b/selfdrive/common/mat.h
@@ -1,4 +1,5 @@
-#pragma once
+#ifndef COMMON_MAT_H
+#define COMMON_MAT_H
 
 typedef struct vec3 {
 	float v[3];
@@ -16,7 +17,7 @@ typedef struct mat4 {
   float v[4*4];
 } mat4;
 
-static inline mat3 matmul3(const mat3 &a, const mat3 &b) {
+static inline mat3 matmul3(const mat3 a, const mat3 b) {
   mat3 ret = {{0.0}};
   for (int r=0; r<3; r++) {
     for (int c=0; c<3; c++) {
@@ -30,7 +31,7 @@ static inline mat3 matmul3(const mat3 &a, const mat3 &b) {
   return ret;
 }
 
-static inline vec3 matvecmul3(const mat3 &a, const vec3 &b) {
+static inline vec3 matvecmul3(const mat3 a, const vec3 b) {
   vec3 ret = {{0.0}};
   for (int r=0; r<3; r++) {
     for (int c=0; c<3; c++) {
@@ -40,7 +41,7 @@ static inline vec3 matvecmul3(const mat3 &a, const vec3 &b) {
   return ret;
 }
 
-static inline mat4 matmul(const mat4 &a, const mat4 &b) {
+static inline mat4 matmul(const mat4 a, const mat4 b) {
   mat4 ret = {{0.0}};
   for (int r=0; r<4; r++) {
     for (int c=0; c<4; c++) {
@@ -54,7 +55,7 @@ static inline mat4 matmul(const mat4 &a, const mat4 &b) {
   return ret;
 }
 
-static inline vec4 matvecmul(const mat4 &a, const vec4 &b) {
+static inline vec4 matvecmul(const mat4 a, const vec4 b) {
   vec4 ret = {{0.0}};
   for (int r=0; r<4; r++) {
     for (int c=0; c<4; c++) {
@@ -66,7 +67,7 @@ static inline vec4 matvecmul(const mat4 &a, const vec4 &b) {
 
 // scales the input and output space of a transformation matrix
 // that assumes pixel-center origin.
-static inline mat3 transform_scale_buffer(const mat3 &in, float s) {
+static inline mat3 transform_scale_buffer(const mat3 in, float s) {
   // in_pt = ( transform(out_pt/s + 0.5) - 0.5) * s
 
   mat3 transform_out = {{
@@ -83,3 +84,5 @@ static inline mat3 transform_scale_buffer(const mat3 &in, float s) {
 
   return matmul3(transform_in, matmul3(in, transform_out));
 }
+
+#endif
diff --git a/selfdrive/modeld/SConscript b/selfdrive/modeld/SConscript
index 15076e5c9d..18f279bf78 100644
--- a/selfdrive/modeld/SConscript
+++ b/selfdrive/modeld/SConscript
@@ -6,10 +6,10 @@ libs = [cereal, messaging, common, 'OpenCL', 'SNPE', 'symphony-cpu', 'capnp', 'z
 TEST_THNEED = False
 
 common_src = [
-  "models/commonmodel.cc",
+  "models/commonmodel.c",
   "runners/snpemodel.cc",
   "transforms/loadyuv.c",
-  "transforms/transform.cc"
+  "transforms/transform.c"
 ]
 
 if arch == "aarch64":
diff --git a/selfdrive/modeld/models/commonmodel.cc b/selfdrive/modeld/models/commonmodel.c
similarity index 100%
rename from selfdrive/modeld/models/commonmodel.cc
rename to selfdrive/modeld/models/commonmodel.c
diff --git a/selfdrive/modeld/transforms/transform.cc b/selfdrive/modeld/transforms/transform.c
similarity index 96%
rename from selfdrive/modeld/transforms/transform.cc
rename to selfdrive/modeld/transforms/transform.c
index 53e7fc488c..0b4150ddb2 100644
--- a/selfdrive/modeld/transforms/transform.cc
+++ b/selfdrive/modeld/transforms/transform.c
@@ -99,14 +99,14 @@ void transform_queue(Transform* s,
   err = clSetKernelArg(s->krnl, 10, sizeof(cl_mem), &s->m_y_cl);
   assert(err == 0);
 
-  const size_t work_size_y[2] = {(size_t)out_y_width, (size_t)out_y_height};
+  const size_t work_size_y[2] = {out_y_width, out_y_height};
 
   err = clEnqueueNDRangeKernel(q, s->krnl, 2, NULL,
                               (const size_t*)&work_size_y, NULL, 0, 0, NULL);
   assert(err == 0);
 
 
-  const size_t work_size_uv[2] = {(size_t)out_uv_width, (size_t)out_uv_height};
+  const size_t work_size_uv[2] = {out_uv_width, out_uv_height};
 
   err = clSetKernelArg(s->krnl, 1, sizeof(cl_int), &in_uv_width);
   assert(err == 0);
diff --git a/selfdrive/modeld/visiontest.mk b/selfdrive/modeld/visiontest.mk
index 7bd3852dc8..494e00f81f 100644
--- a/selfdrive/modeld/visiontest.mk
+++ b/selfdrive/modeld/visiontest.mk
@@ -48,7 +48,7 @@ endif
 all: visiontest
 
 libvisiontest_inputs := visiontest.c \
-                        transforms/transform.cc \
+                        transforms/transform.c \
                         transforms/loadyuv.c \
                         ../common/clutil.c \
                         $(BASEDIR)/selfdrive/common/util.c \