Need help with code

Hi everyone!
Here is the code:

Code:

 USE16
        ORG 7C00h

        START1:

        jmp START

        DATASECT:

        DAP:
        DAP_Size             db 10h         ;1h
        DAP_Res1             db 0           ;2h
        DAP_Bytes2Transfer   db 1h          ;3h
        DAP_Res2             db 0           ;4h
        DAP_Buff_Addr1       dw 7FFh        ;6h
        DAP_Buff_Addr2       dw 0h          ;8h
        DAP_LBA              dq 1h          ;11h

        DAT:
        DAT_Disk_Num         db 80h         ;12h          number of device 80h-winchester
        DAT_Num_Of_Sects     dw 1h          ;13h          the number of 512byte sectors, that contain your kernel your kernel + 1

        GDT:
        GDT_DESC:
                    dw GDT_ENDS - GDT_STARTS - 1h            ;15h
                    dd GDT_STARTS                            ;17h

        GDT_STARTS:


        GDT_REC0    dq 0h                                    ;1Bh


        GDT_REC1    dw 0FFFFh        ;code segment           ;23h
                    dw 0h
                    db 0h
                    db 10011010b
                    db 11001111b
                    db 0h
        GDT_REC2    dw 0FFFFh        ;data segment           ;2Bh
                    dw 0h
                    db 0h
                    db 10010010b
                    db 11001111b
                    db 0h
        GDT_ENDS:    ;all these are resource that ill need later

        START:

        MOV_:
        mov bp, 9FA0h
        mov ds, bp
        mov bp, 7BFFh
        mov cx, 510d

        MOV_LOOP:
        mov si, cx
        mov al, [cs:bp+si]
        mov [ds:si], al
        loop MOV_LOOP

        CHANGE_PLACE:
        mov bp, JUMP_POINT - START1 + 1
        jmp far [ds:bp]


        JUMP_POINT:

        HAPPY_END:
        nop
        jmp HAPPY_END

        times 429 db 0
        dw 0AA55h

It have to move boot sector to high memory location 9FA00h, and jump to execute code in that location, but it fails on CHANGE_PLACE procedure(I checked rest of the code without it and it worked properly)
Why?