[solved] EFI_INVALID_PARAMETER on calling OpenProtocol()

Hi in my UEFI bootloader using FASM Assembly, I am trying to get my loaded image protocol interface structure using BS->OpenProtocol() function call. I am getting `EFI_INVALID_PARAMETER` as the result. As per my checks, the handle, the protocol and the interface are not NULL and I am passing the 5th and 6th arguments in stack from right-to-left and they are 8-byte aligned too. What am I missing? Any idea? Thank you.

Code:

; UEFI Bootloader using FASM Assembly
format pe64 efi

entry start

; EFI Constants
EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL = 0x00000001

EFIERR = 0x8000000000000000
EFI_INVALID_PARAMETER = EFIERR or 0x2


section '.text' code executable readable
start:
  push rbp
  mov [image_handle], rcx
  mov [system_table], rdx

  ...

  ; Get our loaded image protocol interface structure.
  ; Invoke ST->BootServices->OpenProtocol() function.
  mov rax, [system_table]
  mov rcx, [rax + 96]
  mov r10, [rcx + 280]

  mov rcx, [image_handle]
  lea rdx, [EFI_LOADED_IMAGE_PROTOCOL_GUID]
  lea r8, [boot_img]
  mov r9, rcx
  sub rsp, 32
  mov eax, EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL
  push rax
  xor eax, eax
  push rax
  call r10
  pop rcx
  pop rcx
  add rsp, 32
  mov rcx, EFI_INVALID_PARAMETER
  cmp rax, rcx
  je .hang

  ...

.hang:
  jmp $

  ...



section '.data' data readable writable

image_handle dq 0
system_table dq 0

; Image that we booted from.
boot_img dq 0

EFI_LOADED_IMAGE_PROTOCOL_GUID:
  dd 0x5b1b31a1
  dw 0x9562
  dw 0x11d2
  db 0x8e, 0x3f, 0x00, 0xa0, 0xc9, 0x69, 0x72, 0x3b