diff --git a/boot.s b/boot.s
index 77d02aa..86fe87c 100644
--- a/boot.s
+++ b/boot.s
@@ -223,7 +223,7 @@ digit_loop:
 	incw %cs:_sector_num+1
 read_sector:
 _sector_num:
-	movw $1, %ax  # sector num
+	movw $0, %ax  # sector num (0indexed)
 	movb $18, %ch # divide by 18 (sectors / track)
 	div %ch
 	# %ah - sector
@@ -233,8 +233,9 @@ _sector_num:
 	and %al, %dh
 	sar $1, %al
 
-	mov %al, %ch  # track
+	mov %al, %ch # track
 	mov %ah, %cl # sector
+	inc %cl      # sectors are 1indexed
 
 	mov $1, %al  # read only one sector
 	xor %bx, %bx # write to es:bx