🚀 go-pugleaf

I'm currently writing a program where I need to read the boot-
sector without using DOS calls.
So instead I'm using INT 13h subfunction: AH=02h: Read Sectors
Into Memory.
The following code works fine, if I try to read the bootsector
of drive A: (dl=00h), but I can't read the bootsector of my
harddisk (dl=80h), instead I get the logical sector 3100h. Why?

        ...
        
        ; DL = Physical Drive Number
        mov     ax,0201h        ; Read One Sector
        mov     dh,00h          ; Side 0
        mov     cx,0001h	; Track 0, Sector 1
	mov	bx,offset BoSec ; Store address
	int	13h		; Execute function

	...

I'm running DOS 4.1 with a 49MB SCSI harddisk, with one big partion
(16 bit FAT), and I will be very pleased if someone could help me!