diff --git a/presets/nes/flicker.c b/presets/nes/flicker.c
index 6f8a9907..dbec9387 100644
--- a/presets/nes/flicker.c
+++ b/presets/nes/flicker.c
@@ -21,7 +21,7 @@ metasprite.
 ///// METASPRITES
 
 #define TILE 0xd8
-#define ATTR 0
+#define ATTR 0x0
 
 // define a 2x2 metasprite
 const unsigned char metasprite[]={
diff --git a/presets/nes/sprites.c b/presets/nes/sprites.c
index 9d38a1ed..1559e873 100644
--- a/presets/nes/sprites.c
+++ b/presets/nes/sprites.c
@@ -39,22 +39,21 @@ void setup_graphics() {
 }
 
 // number of actors
-#define NUM_ACTORS 64
+#define NUM_ACTORS 64		// 64 sprites (maximum)
 
 // actor x/y positions
-byte actor_x[NUM_ACTORS];
-byte actor_y[NUM_ACTORS];
+byte actor_x[NUM_ACTORS];	// horizontal coordinates
+byte actor_y[NUM_ACTORS];	// vertical coordinates
+
 // actor x/y deltas per frame (signed)
-sbyte actor_dx[NUM_ACTORS];
-sbyte actor_dy[NUM_ACTORS];
+sbyte actor_dx[NUM_ACTORS];	// horizontal velocity
+sbyte actor_dy[NUM_ACTORS];	// vertical velocity
 
 // main program
 void main() {
   char i;	// actor index
   char oam_id;	// sprite ID
   
-  // initialize PPU
-  setup_graphics();
   // initialize actors with random values
   for (i=0; i<NUM_ACTORS; i++) {
     actor_x[i] = rand();
@@ -62,6 +61,8 @@ void main() {
     actor_dx[i] = (rand() & 7) - 3;
     actor_dy[i] = (rand() & 7) - 3;
   }
+  // initialize PPU
+  setup_graphics();
   // loop forever
   while (1) {
     // start with OAMid/sprite 0
diff --git a/src/worker/workermain.ts b/src/worker/workermain.ts
index bfede6cf..1acf4115 100644
--- a/src/worker/workermain.ts
+++ b/src/worker/workermain.ts
@@ -540,6 +540,7 @@ function setupFS(FS, name:string) {
   }, '/share');
   // fix for slow Blob operations by caching typed arrays
   // https://github.com/kripken/emscripten/blob/incoming/src/library_workerfs.js
+  // https://bugs.chromium.org/p/chromium/issues/detail?id=349304#c30
   var reader = WORKERFS.reader;
   var blobcache = {};
   WORKERFS.stream_ops.read = function (stream, buffer, offset, length, position) {