Bootloader - Doesn't jmp or load second sector correctly

Question

I've been desperatly trying to make a bootloader. At a point I got it working but now it doesn't work anymore. When I run it, it prints an A and a B. So that means it does actualy do the read, but for some reason when it jumps it doesn't execute the code I put at the second sector of my USB drive.

I wonder if there's something wrong with my adressing or jumps?

I included the image of my USB memory

[bits 16]
[org 0x7C00]

jmp Start

;%include "BIOS_Parameter_Block.inc"
;%include "Extensions.inc"
;%include "Print.inc"

; Prepare Stack Segment
;-----------------------------------------------------------------
Start:
xor ax, ax
mov ds, ax
mov es, ax
mov fs, ax
mov gs, ax
mov ss, ax

mov sp, 0x7C00              ; Move Stack into SP
mov bp, sp                  ; Store current Stack Base

; Print Character to Make Sure Bootloader Has Reached this Point
;-----------------------------------------------------------------
mov ah, 0x0E                ; Print Character to Screen
mov bh, 0x00                ; No Page Numbering
mov bl, 0x07                ; White Text, Black Background
mov al, 65                  ; Print Letter A
int 0x10

; Check if INT0x13 Extentions are Supported
;-----------------------------------------------------------------
mov ah, 0x41                ; Set Function 0x41
mov word bx, 0x55AA          
push dx                     ; Save old Drive Identifier
mov dl, 0x80                ; Load 'Active' ID Into dl
int 0x13                    ; Call Interupt
jc short unsupported        ; If Extentions aren't Supported, Jump
clc                         ; Clear Carry Bit

; Read from the device.
;-----------------------------------------------------------------
mov si, DAPS                ; Load DAPS Struct to DS:SI
mov ah, 0x42                ; Read Functions (AL Ignored)
mov dl, 0x80                ; Load 'Active' ID Into dl
int 0x13
jc short unsupported        ; If something goes wrong...

mov ah, 0x0E                ; Print Character to Screen
mov bh, 0x00                ; No Page Numbering
mov bl, 0x07                ; White Text, Black Background
mov al, 66                  ; Print Letter B
int 0x10

; IT DOES PRINT THIS ABOVE

jmp 0x0:0x7E00                  ; Jump to main

; Errors 
;-----------------------------------------------------------------
unsupported:
mov ah, 0x0E                ; Print Letter F, Gives Indication of Failure
mov bh, 0x00
mov bl, 0x07
mov al, 70
int 0x10

clc
hlt
; Memory Data Structures and Other Variables
;-----------------------------------------------------------------
; Disk Address Packet Structure (Used For Loading Rest of OS)
DAPS: db 0x10               ; Size of Structure (16 bytes)
      db 0                  ; Always 0
      dw 1                  ; Number of Sectors to Read (1x512)
      dw 0x7E00             ; Offset to load to.
      dw 0x0000             ; Segment to load to.
      dq 1                  ; Read from Second Block

; Fill Out Rest of Bootloader
;-----------------------------------------------------------------
times 510-($-$$) db 0

db 0x55, 0xAA               ; Add Boot Record Signature

Stage2 placed at the second sector

 [ORG 0x7E00]
 [bits 16]

 mov ah, 0x0E                ; Print Character to Screen
 mov bh, 0x00                ; No Page Numbering
 mov bl, 0x07                ; White Text, Black Background
 mov al, 67                  ; Print Letter C
 int 0x10
 cli
 hlt

Hope you guys could help me!

Answer 1

int 0x13 bios calls generally use the drive ID in the DL register - 0x80 is usually the ID of the first HDD. You may need to change this in order to load the additional sector from a USB drive (which presumably is not the first HDD).