TIM4 runs at 96MHz, not 48MHz

build/timer.S

@@ -56,7 +56,7 @@ tim4_init:
 	.loc 1 14 35
 	ldr	r3, .L2+4
 	.loc 1 14 41
-	movw	r2, #47999
+	movw	r2, #30463
 	str	r2, [r3, #40]
 	.loc 1 17 35
 	ldr	r3, .L2+4

build/timer.i

@@ -2137,7 +2137,7 @@ void tim4_init(void) {
 
 
 
-  ((struct timer *) (0x40000800U))->PSC = (uint16_t) 48000 - 1;
+  ((struct timer *) (0x40000800U))->PSC = (uint16_t) 96000 - 1;
 
 
   ((struct timer *) (0x40000800U))->ARR = (uint16_t) 0xFFFF;