diff --git a/kernel/sdc.asm b/kernel/sdc.asm
index 1b63214..187e966 100644
--- a/kernel/sdc.asm
+++ b/kernel/sdc.asm
@@ -91,17 +91,17 @@ sdcWakeUp:
 	ld	b, 10		; 10 * 11 == 110
 	ld	a, 0xff
 .loop:
-	out	(SDC_PORT_SPI), a
-	djnz	.loop
+	out	(SDC_PORT_SPI), a	;11 cycles
+	djnz	.loop			;13 cycles
 	ret
 
 ; Initiate SPI exchange with the SD card. A is the data to send. Received data
 ; is placed in A.
 sdcSendRecv:
 	out	(SDC_PORT_SPI), a
-	push 	hl		; nop, pairs with pop later
+	push 	hl		; nop, --> lvl 1
 	in	a, (SDC_PORT_SPI)
-	pop	hl		; nop, pairs with earlier push
+	pop	hl		; nop, <-- lvl 1
 	ret
 
 sdcIdle: