Metroid: Zero Mission (Europe) (Virtual Console) Is Unplayable

[emariz]

Probably not an issue of Open AGB Firm, just a note to other users: the ROM Metroid: Zero Mission (Europe) (Virtual Console) seems to be unplayable; it halts at a white screen upon load.
The ROM's integrity was verified before testing the different save types, none worked.

Its page at No Intro's database:
https://datomatic.no-intro.org/index.php?page=show_record&s=23&n=x159

Granted, this is a Trusted - Not Verified dump, but other ROMs that halt at a white screen do play after the correct save type is selected. This one failed to load after trying all save type options.

[profi200]

I keep getting distracted. I will take a look at this and the other issue later. In the meantime make sure the save type database is up to date.

[profi200]

This VC dump is patched to high hell with emulator specific looking code + some extra headers/footers.

The first instruction in the ROM has been patched to jump to 0x8784000. At that offset i see instructions which are not valid on ARM7. For example:
8784008: ee801000 cdp 0, 8, cr1, cr0, cr0, {0}

This will likely never run correctly on hardware.

[profi200]

With this patch the game seems to run fine. It removes the weird jump to 0x08784000 so the invalid code never gets executed but i can't guarantee that they didn't add more weird patches.

Patch the game with armips. https://github.com/Kingcom/armips

.gba
.arm


; Helpful constants.
rom_start          equ 0x08000000
rom_entry_branch   equ rom_start
multiboot_branch   equ rom_start + 0xC0
input_file_name    equ "metroid_vc.gba"
output_file_name   equ "metroid_vc_patched.gba"



.create output_file_name, rom_start
.org rom_entry_branch
	b multiboot_branch

.incbin input_file_name, 4

.Close