diff --git a/Makefile.firmware b/Makefile.firmware
index c175184f0c..88766774de 100644
--- a/Makefile.firmware
+++ b/Makefile.firmware
@@ -142,6 +142,7 @@ OBJ_MP += $(addprefix $(BUILD_MP)/,\
 	lib/libm/kf_tan.o \
 	lib/libm/log1pf.o \
 	lib/libm/math.o \
+	lib/libm/nearbyintf.o \
 	lib/libm/roundf.o \
 	lib/libm/sf_cos.o \
 	lib/libm/sf_erf.o \
diff --git a/micropython/firmware/main.c b/micropython/firmware/main.c
index ceee2f0430..46309aab45 100644
--- a/micropython/firmware/main.c
+++ b/micropython/firmware/main.c
@@ -8,6 +8,7 @@
 #include "py/stackctrl.h"
 #include "py/repl.h"
 #include "py/gc.h"
+#include "py/mperrno.h"
 #include "lib/utils/pyexec.h"
 
 #include "gccollect.h"
@@ -98,6 +99,6 @@ mp_obj_t mp_builtin_open(uint n_args, const mp_obj_t *args, mp_map_t *kwargs) {
 }
 MP_DEFINE_CONST_FUN_OBJ_KW(mp_builtin_open_obj, 1, mp_builtin_open);
 
-int mp_reader_new_file(mp_reader_t *reader, const char *filename) {
-    return 2; // assume error was "file not found"
+void mp_reader_new_file(mp_reader_t *reader, const char *filename) {
+    mp_raise_OSError(MP_ENOENT); // assume "file not found"
 }
diff --git a/vendor/micropython b/vendor/micropython
index bbdaf762cf..bf2d7b1093 160000
--- a/vendor/micropython
+++ b/vendor/micropython
@@ -1 +1 @@
-Subproject commit bbdaf762cf45518b1f8188b9a951e8459dcc73e3
+Subproject commit bf2d7b10934242b56833d30a91d0ce1beae097e0