diff --git a/amd64/Development/hex0.S b/amd64/Development/hex0.S
index d6c9d27..bf9ed9d 100644
--- a/amd64/Development/hex0.S
+++ b/amd64/Development/hex0.S
@@ -2,34 +2,80 @@
 #
 # SPDX-License-Identifier: GPL-3.0-or-later
 
+# Usage hex0 file.hex0 file
+# Does not validate the arguments
+
 # Calling convention:
-# First four arguments are passed via registers but we need to leave stack space
+# First four arguments are passed via registers rcx, rdx, r8, r9 (if they fit in 64-bits)
+# but we need to leave stack space
 
 .global _start
 .text
 
 _start:
-        sub  rsp, 64
         mov  [ImageHandle], rcx            # ImageHandle *image_handle
         mov  rax, [rdx+96]                 # system->boot
         mov  [SystemBoot], rax             # save system->boot
 
         # Open Loaded Image protocol
+        sub  rsp, 72                       # allocate stack
                                            # arg1 = ImageHandle
         mov  rdx, [LOADED_IMAGE_PROTOCOL]  # EFI_LOADED_IMAGE_PROTOCOL_GUID (first 64 bits)
         mov  [rsp+48], rdx                 # save onto stack
         mov  rdx, [LOADED_IMAGE_PROTOCOL+8]# EFI_LOADED_IMAGE_PROTOCOL_GUID (last 64 bits)
         mov  [rsp+56], rdx                 # save onto stack
         lea  rdx, [rsp+48]                 # arg2 = &EFI_LOADED_IMAGE_PROTOCOL_GUID
-                                           # arg3 = &image
+        lea  r8, [rsp+64]                  # arg3 = &image
         mov  r9, rcx                       # arg4 = image_handle
         mov  qword ptr [rsp+32], 0         # arg5 = NULL
         mov  qword ptr [rsp+40], 1         # arg6 = EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL
 
         call [rax+280]                     # system->boot->open_protocol();
-        add  rsp, 64
 
         # Command line args
+        mov  rax, [rsp+64]                 # get image
+        mov  rcx, rax                      # save image
+        mov  rax, [rax+56]                 # options = image->load_options
+
+loop_options1:                             # Skip application name
+        add  rax, 2                        # ++options
+        mov  bl, [rax]                     # *options
+        cmp  bl, 0x20                      # if *options != ' '
+        jne  loop_options1                 # then jump
+
+        add  rax, 2                        # ++options
+        push rax                           # in = options
+
+loop_options2:                             # Skip argv[1]
+        add  rax, 2                        # ++options
+        mov  bl, [rax]                     # *options
+        cmp  bl, 0x20                      # if *options != ' '
+        jne  loop_options2                 # then jump
+
+        mov  qword ptr [rax],              # *options = 0;
+        add  rax, 2                        # ++options
+        push rax                           # out = options
+
+        # Get root device
+        sub  rsp, 72                       # allocate stack
+        mov  rcx, [rcx+24]                 # arg1 = root_device = image->device
+        mov  rdx, [SIMPLE_FS_PROTOCOL]     # EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID (first 64 bits)
+        mov  [rsp+48], rdx                 # save onto stack
+        mov  rdx, [SIMPLE_FS_PROTOCOL+8]   # EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID (last 64 bits)
+        mov  [rsp+56], rdx                 # save onto stack
+        lea  rdx, [rsp+48]                 # arg2 = &EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID
+        lea  r8, [rsp+64]                  # arg3 = &root_fs
+        mov  r9, [ImageHandle]             # arg4 = image_handle
+        mov  qword ptr [rsp+32], 0         # arg5 = NULL
+        mov  qword ptr [rsp+40], 1         # arg6 = EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL
+
+        mov  rax, [SystemBoot]             # system->boot
+        call [rax+280]                     # system->boot->open_protocol();
+        mov  r8, [rsp+64]                  # get root_fs
+        add  rsp, 144                      # deallocate stack
+
+        pop  r8                            # out
+        pop  r8                            # in
 
 Done:
         ret
@@ -45,3 +91,9 @@ LOADED_IMAGE_PROTOCOL:
 .short 0x9562
 .short 0x11d2
 .byte 0x8e, 0x3f, 0x00, 0xa0, 0xc9, 0x69, 0x72, 0x3b
+
+SIMPLE_FS_PROTOCOL:
+.long  0x0964e5b22
+.short 0x6459
+.short 0x11d2
+.byte 0x8e, 0x39, 0x00, 0xa0, 0xc9, 0x69, 0x72, 0x3b