diff --git a/firmware/main.c b/firmware/main.c
index d96f667..7a076ef 100644
--- a/firmware/main.c
+++ b/firmware/main.c
@@ -38,7 +38,7 @@ void init()
     PORTD = 0b01000000;
 
     // Setup Timer-Interrupt "TIMER1" compare match interrupt
-    TIMSK |= (1 << OCIE1A);
+    TIMSK = (1 << OCIE1A);
 
     // Refreshrate is 100Hz of the whole LEDCube.
     // The ISR comes up at 300Hz.
@@ -48,7 +48,7 @@ void init()
     OCR1AL = 0b01110001;
 
     // Set prescale to 64 and clear the counter on compare match.
-    TCCR1B |= (1 << CS11) | (1 << CS10) | (1 << WGM12);
+    TCCR1B = (1 << CS11) | (1 << CS10) | (1 << WGM12);
 
     sei(); // Enable interrupts global
 }
@@ -57,8 +57,7 @@ void init()
  */
 ISR (TIMER1_COMPA_vect)
 {
-
-    if ( !(--delay) ) // decrease the counter and check if we are done with waiting
+    if (!(--delay)) // decrease the counter and check if we are done with waiting
     {
         if (frmnum == MAX_EEPROM_FRAMES)
         {
@@ -82,6 +81,7 @@ ISR (TIMER1_COMPA_vect)
     }
 
     // !!!Don't touch the 6th bit (9th LED wire)!!!
+    // PORTD = __, 9, C, B, A, D+, D-, __
     PORTD &= 0b11000111; // delete bit 3 to 6 (bit 3 to 5 = layer 0 to 2
 
     uint8_t tmp = level * 9; // calculate the position in the frame
@@ -90,7 +90,7 @@ ISR (TIMER1_COMPA_vect)
     // 0 = led is on, 1 = led is off
     PORTB = ~((frame >> tmp) & 0xff);
 
-    if ( (((frame >> tmp) >> 8) & 0x01) )
+    if ((((frame >> tmp) >> 8) & 0x01))
         PORTD &= ~(1 << 6); // turn the 9th LED on
     else
         PORTD |=  (1 << 6); // turn the 9th LED off