Standalone payload.elf loader

This is .rpx is meant to run in a envrionment with sd and codegen (jit) access. It's exploits the Cafe OS and maps 8 MiB of usable memory from 0x30000000...0x30800000 (physical address) to 0x00800000... 0x01000000 (virtual address) where a payload will be loaded. You may need to hook into the kernel and patch out some thing to gain persistent access to this area. The loaded payload.elf needs to be mapped to this memory area.

Usage

Put the payload.elf in the sd:/wiiu/ folder of your sd card and start the application. If no payload.elf was found on the sd card, a IOSU exploit will be executed which forces the default title id to the Wii U Menu (in case of system.xml changes)

Special button combinations:

Hold R while launching to skip payload.elf launching.

Reset the default title id

When loading this payload in a coldboot environment a payload.elf may want to force the default title id to the Wii U Menu. This loader offers some callbacks to the payload.elf to achieve such behaviour. The payload.elf will be loaded with some special arguments. As normal, the first argument is the name of current running RPX, but afterwards a list of callbacks is provided.

Example implementation of the loader:

argc = 3;
argv[0] = "safe.rpx";                                       // original argument
argv[1] = "void forceDefaultTitleIDToWiiUMenu(void)";       // signature of the first callback function
argv[2] = &forceDefaultTitleIDToWiiUMenu;                   // pointer to first callback function.
int res = ((int (*)(int, char **)) entryPoint)(argc, arr);  // call the payload.elf with some special arguments.

Inside the payload.elf you may want to do something like this:

for (int i = 0; i < argc; i++) {
            if(strcmp(argv[i], "void forceDefaultTitleIDToWiiUMenu(void)") == 0){
                if((i + 1) < argc){
                    i++;
                    void (*forceDefaultTitleIDToWiiUMenu)(void) = (void (*)(void)) argv[i];
                    forceDefaultTitleIDToWiiUMenu();
                }
            }
        }

Currently the following callbacks are provided:

void forceDefaultTitleIDToWiiUMenu(void) = Reverts the coldboot into a specific title by forcing it the Wii U Menu. Caution: This will perform a IOSU exploit.

Building

Make you to have wut installed and use the following command for build:

make

Building using the Dockerfile

It's possible to use a docker image for building. This way you don't need anything installed on your host system.

# Build docker image (only needed once)
docker build . -t payloadfromrpx-builder

# make 
docker run -it --rm -v ${PWD}:/project payloadfromrpx-builder make

# make clean
docker run -it --rm -v ${PWD}:/project payloadfromrpx-builder make clean

Format the code via docker

docker run --rm -v ${PWD}:/src wiiuenv/clang-format:13.0.0-2 -r ./source -i

Credits

orboditilt
Maschell
many many more

Parts taken from:

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