diff --git a/SConscript.firmware b/SConscript.firmware
index 74c3584b..d213ab02 100644
--- a/SConscript.firmware
+++ b/SConscript.firmware
@@ -141,7 +141,6 @@ SOURCE_MICROPYTHON = [
     'vendor/micropython/py/emitinlinextensa.c',
     'vendor/micropython/py/formatfloat.c',
     'vendor/micropython/py/frozenmod.c',
-    'vendor/micropython/py/gc.c',
     'vendor/micropython/py/lexer.c',
     'vendor/micropython/py/malloc.c',
     'vendor/micropython/py/map.c',
@@ -221,7 +220,6 @@ SOURCE_MICROPYTHON = [
     'vendor/micropython/py/stackctrl.c',
     'vendor/micropython/py/stream.c',
     'vendor/micropython/py/unicode.c',
-    'vendor/micropython/py/vm.c',
     'vendor/micropython/py/vstr.c',
     'vendor/micropython/py/warning.c',
     'vendor/micropython/stmhal/gccollect.c',
@@ -231,6 +229,11 @@ SOURCE_MICROPYTHON = [
     'vendor/micropython/stmhal/systick.c',
 ]
 
+SOURCE_MICROPYTHON_SPEED = [
+    'vendor/micropython/py/gc.c',
+    'vendor/micropython/py/vm.c',
+]
+
 SOURCE_STMHAL = [
     'vendor/micropython/stmhal/hal/f4/src/stm32f4xx_hal_adc_ex.c',
     'vendor/micropython/stmhal/hal/f4/src/stm32f4xx_hal_adc.c',
@@ -286,7 +289,7 @@ SOURCE_TREZORHAL = [
     'embed/trezorhal/hal/stm32f4xx_ll_fsmc.c',
 ]
 
-SOURCE_QSTR = SOURCE_MOD + SOURCE_MICROPYTHON
+SOURCE_QSTR = SOURCE_MOD + SOURCE_MICROPYTHON + SOURCE_MICROPYTHON_SPEED
 
 # TODO: recursive Glob
 SOURCE_PY = Glob('src/*.py')
@@ -311,7 +314,8 @@ env.Replace(
     OBJCOPY='arm-none-eabi-objcopy', )
 
 env.Replace(
-    CCFLAGS='-Os '
+    COPT='-Os',
+    CCFLAGS='$COPT '
     '-g3 '
     '-nostdlib '
     '-std=gnu99 -Wall -Werror -Wdouble-promotion -Wpointer-arith '
@@ -319,6 +323,7 @@ env.Replace(
     '-fsingle-precision-constant -fdata-sections -ffunction-sections ' +
     CCFLAGS_MOD,
     CCFLAGS_QSTR='-DNO_QSTR -DN_X64 -DN_X86 -DN_THUMB',
+    CCFLAGS_OPT='-O3',
     LINKFLAGS='-nostdlib -T embed/firmware/memory.ld --gc-sections',
     CPPPATH=[
         '.',
@@ -394,6 +399,7 @@ obj_program = []
 obj_program.extend(env.Object(source=SOURCE_MOD))
 obj_program.extend(env.Object(source=SOURCE_FIRMWARE))
 obj_program.extend(env.Object(source=SOURCE_MICROPYTHON))
+obj_program.extend(env.Object(source=SOURCE_MICROPYTHON_SPEED, COPT='-O3'))
 obj_program.extend(env.Object(source=SOURCE_STMHAL))
 obj_program.extend(env.Object(source=SOURCE_TREZORHAL))
 obj_program.extend(env.Object(source=source_mpyc))
diff --git a/site_scons/site_tools/micropython/__init__.py b/site_scons/site_tools/micropython/__init__.py
index 7b1f3bb1..a149e6c0 100644
--- a/site_scons/site_tools/micropython/__init__.py
+++ b/site_scons/site_tools/micropython/__init__.py
@@ -26,7 +26,6 @@ def generate(env):
         return '$MPY_CROSS -o %s -s %s %s' % (target, source_name, source)
 
     env['BUILDERS']['FrozenModule'] = SCons.Builder.Builder(
-        # action='$MPY_CROSS -o $TARGET -s $SOURCE $SOURCE',
         generator=generate_frozen_module,
         suffix='.mpy',
         single_source=True, )