diff --git a/animationscene.py b/animationscene.py
index 27e3225..912397d 100755
--- a/animationscene.py
+++ b/animationscene.py
@@ -95,7 +95,7 @@ class AnimationScene:
 		"""
 		Load icon into first available slot
 		"""
-		cols = bytearray(' ' * 32)
+		cols = bytearray(b' ' * 32)
 		icon_width = 8
 		padding = 1 if self.display.columns == 32 else 0
 		for state in self.on_screen_icons:
diff --git a/firescene.py b/firescene.py
index ffc4a88..c77900c 100755
--- a/firescene.py
+++ b/firescene.py
@@ -1,4 +1,7 @@
-from uos import urandom
+try:
+	from uos import urandom
+except:
+	from os import urandom
 from pixelfont import PixelFont
 
 class FireScene:
@@ -70,7 +73,10 @@ class FireScene:
 					put_pixel(x, y, max(r, 0), max(g, 0), b)
 				# Spread heat from below
 				r, g, b = get_pixel(x, y+1)
-				spread = (urandom(1)[0]&3) - 1
+				try:
+					spread = (urandom(1)[0]&3) - 1
+				except TypeError:
+					spread = (ord(urandom(1)[0])&3) - 1
 				r -= spread
 				g -= 1
 				b >>= 2
diff --git a/pixelfont.py b/pixelfont.py
index d65f5bd..31db232 100755
--- a/pixelfont.py
+++ b/pixelfont.py
@@ -5,4 +5,4 @@ class PixelFont:
 	width = 4
 	height = 5
 	alphabet = " %'-./0123456789:?acdefgiklmnoprstwxy"
-	data = bytearray("\x00\x00\x50\x24\x51\x66\x00\x00\x60\x00\x00\x00\x42\x24\x11\x57\x55\x27\x23\x72\x47\x17\x77\x64\x74\x55\x47\x74\x71\x74\x17\x57\x77\x44\x44\x57\x57\x77\x75\x74\x20\x20\x30\x24\x20\x52\x57\x25\x15\x25\x53\x55\x73\x31\x71\x17\x13\x71\x71\x75\x27\x22\x57\x35\x55\x11\x11\x57\x77\x55\x75\x77\x75\x55\x75\x57\x17\x71\x35\x55\x17\x47\x77\x22\x22\x55\x77\x55\x25\x55\x55\x27\x02")
+	data = bytearray(b"\x00\x00\x50\x24\x51\x66\x00\x00\x60\x00\x00\x00\x42\x24\x11\x57\x55\x27\x23\x72\x47\x17\x77\x64\x74\x55\x47\x74\x71\x74\x17\x57\x77\x44\x44\x57\x57\x77\x75\x74\x20\x20\x30\x24\x20\x52\x57\x25\x15\x25\x53\x55\x73\x31\x71\x17\x13\x71\x71\x75\x27\x22\x57\x35\x55\x11\x11\x57\x77\x55\x75\x77\x75\x55\x75\x57\x17\x71\x35\x55\x17\x47\x77\x22\x22\x55\x77\x55\x25\x55\x55\x27\x02")
diff --git a/renderloop.py b/renderloop.py
index 3634fdf..769ef2d 100755
--- a/renderloop.py
+++ b/renderloop.py
@@ -3,7 +3,7 @@ import time
 import gc
 from math import ceil
 
-if not hasattr(time, 'ticks_ms'):
+if not hasattr(time, 'sleep_ms') or not hasattr(time, 'ticks_ms'):
 	# Emulate https://docs.pycom.io/firmwareapi/micropython/utime.html
 	time.ticks_ms = lambda: int(time.time() * 1000)
 	time.sleep_ms = lambda x: time.sleep(x/1000.0)
diff --git a/scripts/generate-pixelfont.py b/scripts/generate-pixelfont.py
index 8762398..4e8758e 100755
--- a/scripts/generate-pixelfont.py
+++ b/scripts/generate-pixelfont.py
@@ -96,7 +96,7 @@ if __name__ == '__main__':
 	print('width = {}'.format(font_width))
 	print('height = {}'.format(font_height))
 	print('alphabet = "{}"'.format(font_alphabet))
-	print('data = bytearray("{}")'.format("".join("\\x{:02x}".format(x) for x in data)))
+	print('data = bytearray(b"{}")'.format("".join("\\x{:02x}".format(x) for x in data)))
 	print('')
 	print('/* Computed with pixelfont.py */')
 	print('static int font_width = {};'.format(font_width))