Bootloader fails to load kernel beyond specified memory location

Question

I'm encountering an issue with my bootloader code where it fails to load the kernel beyond a certain memory location, specifically at KERNEL_LOCATION equ 0x100000. When attempting to boot using QEMU, I receive the error message "boot failed: could not read the boot disk."

Here's the relevant part of my bootloader code:

[org 0x7c00]

KERNEL_LOCATION equ 0x100000
BOOT_DISK equ 0

xor ax, ax
mov es, ax
mov ds, ax
mov bp, 0x9000
mov sp, bp


call read_disk

init_pm:
    mov ax, 0x0003
    int 10h

    cli
    lgdt [GDT_descriptor]

    mov eax, cr0
    or eax, 1
    mov cr0, eax

    jmp CODE_SEG:start_protected_mode

%include "gdt.asm"
%include "read_disk.asm"

[bits 32]
start_protected_mode:
    mov eax, DATA_SEG
    mov ds, eax
    mov ss, eax
    mov es, eax
    mov fs, eax
    mov gs, eax

    mov ebp, KERNEL_LOCATION      ; 32 bit stack base pointer
    mov esp, ebp

    jmp dword KERNEL_LOCATION     ; Jump to the kernel's entry point

times 510-($-$$) db 0
dw 0xaa55

here is the read disk function:

read_disk:

    ; bios read functions
    mov ah, 0x02

    ; reading just one sector
    mov al, 10

    ; chs addressing
    mov ch, 0x00 ; cylender
    mov dh, 0x00 ; head
    mov cl, 0x02 ; sector (reading the first sector after the boot sector sectors start at 1)


    ; setting the bx to the address we want to load our read disk
    mov bx, KERNEL_LOCATION

    mov dl, BOOT_DISK

    int 0x13  
    ; jump to error handler if c flag is one
    ; jc disk_error

    ; returning to the caller address
    ret

; error handler
disk_error:
    mov bx, error_msg
    ;call print_string
    jmp $

error_msg:
    ; null terminating string :)
    db "error reading disk",0

The read_disk function seems to be functioning properly, as it loads the boot sector correctly. However, when trying to load the kernel at 0x100000, it fails.

Notably, if I specify a lower memory location, such as 0x1000, the bootloader boots properly.

Any insights into why the bootloader fails to load the kernel beyond 0x100000 would be greatly appreciated. Thanks!