Fix the timer ISR name

lib/c/avr.c

@@ -32,7 +32,7 @@
 #include <avr/io.h>
 #include "avr.h"
 
-ISR(TIMER0_OVF_vect) {
+ISR(TIMER1_COMPA_vect) {
   run_timers();
 }
 
@@ -50,7 +50,7 @@ void init_timer1() {
 }
 
 void atomic_memcpy(void *dest, const void *src, size_t size) {
-  ATOMIC_BLOCK(ATOMIC_FORCEON) {
+  ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
     memcpy(dest, src, size);
   }
 }