Booting this over PXE

[veso266]

Hi there, I wanted to test this on a real computer so I decided to try to boot my OS over PXE so I don't need to write floppy disks or USB sticks

But I can't

in Quemu my image works fine (I invoe it like qemu-system-x86_64 whole_os_with_kernel.img)

But as soon as I tried to boot this over PXE with something like tftpd

What is extremly confusing is that if I only boot just a simple boot sector program like this

;
; A simple  boot  sector  that  prints a message  to the  screen  using a BIOS  routine.
;

	mov ah, 0x0e ; int 10/ah = 0eh -> scrolling teletype BIOS routine

	mov al, 'H'
	int 0x10
	mov al, 'e'
	int 0x10
	mov al, 'l'
	int 0x10
	mov al, 'l'
	int 0x10
	mov al, 'o'
	int 0x10

	jmp $ ; Jump to the current address (i.e. forever).


;
; Padding  and  magic  BIOS  number.
;

	times 510-($-$$) db 0 ; Pad the boot sector out with zeros
	
	dw 0xaa55 ; Last two bytes form the magic number ,
			  ; so BIOS knows we are a boot sector.

It works fine

but as soon as I tried to boot something more complex (code is from this repo from 23-fixes folder) , I get garbage on the screen and I don't know why

insitde testOS.zip you will find 2 files

hello_boot_sector.img -- works fine, prints only hello
whole_os_with_kernel.img -- prints garbage on the screen over PXE

testOS.zip

If it helps to diagnoze the problem, both Vmware Vorkstation and Virtual PC 2007 are using Intel PXE ROM

Hope someone knows, whats going on, because I am quite confused