Geckoloader

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geckoloader - coded by dhewg, #wiidev on EFNet

about

geckoloader is a native wii application which helps you to load and execute wii homebrew binaries in the easiest and fastest way possible. It acts as a server which will receive binaries directly using a usbgecko adapter
a client tool to transfer such files is included

requirements

  • a usbgecko adapter
  • a gamecube pad
  • a way to boot wii homebrew

architecture

the application consists of 3 parts
  • stub
  • loader
  • boot
the boot code is what you will be running, it contains the other two parts. it will write the loader code to the onboard usbgecko flash and place the stub into memory
the bootcode will then execute the stub
the stub's job is to read the loader code from flash and execute it
finally, the loader code will accept incoming .dol's sent using a client application from the pc side
the chosen architecture has the advantage that the tiny stub is the only component which has to stay in tact in memory. since the real loader sits on the onboard usbgecko flash, no application can corrupt it in memory

features

  • 100% native wii mode
  • no medium ejecting, rewriting and inserting required whatsoever
  • this is especially useful for wii coders (fast development cycle)
  • the stub is placed at the memory location 0x80001800. this is PSO reload compatible, which means that you can jump back there to load another binary without rebooting. the libogc exception handler also jumps to this address (when pressing START)
  • the included client is compatible to the official geckotool, so you can use nuke's windows client to upload .dol's too
  • as always, this is open source ;)

build

hint: a precompiled binary is included
to compile the included code, you need devkitPPC and libogc r14 or higher
copy stub/stub.lds to $DEVKITPPC/powerpc-gekko/lib
check config.h for some tuneables
run make in the root dir
run make install to copy geckoupload (the client) to $DEVKITPPC/bin

usage

  • use the Twilight hack in combination with the included geckoloader.elf to get this running
  • the boot code will show up
  • you have to write the loader code to the onboard usbgecko flash once, so press Z on a gamecube pad to do that
  • flashing has to be done only once, press A the next time you reboot the wii to skip that step
  • after that you will see the loader code in action
  • use a compatible client (like the included one geckoupload, or the official windows geckotool) to send a .dol
  • the transfered binary should execute
  • if you loaded a game/app which has an option to jump back to 0x80001800, you will be able to transmit another binary without reboot
hint: try to upload the included test.dol first. it just prints a string to screen and has an option to jump back to the loader

client usage

  • set the environment variable USBGECKODEVICE to the tty device of the usbgecko adapter, eg:
export USBGECKODEVICE=/dev/ttyUSB0
  • make sure that your console is ready to receive an executable
  • pass the filename of the binary to geckoupload, for example:
geckoupload test.dol
you can use this client to transfer
  • wii .dol's to the geckoloader described on this page
  • gamecube .dol's to the official usbgecko boot dvd
  • wii .elf's to the upcoming release of the twilight hack

notes

  • please report back how it worked for you!
  • only .dol files are supported
  • you can not run gamecube binaries with this loader since we're working in wiimode here (that's a good thing)
  • the included client will not compile using mingw, patches are welcome
  • the uploaded data is not verified by neither the included client nor the receiving loader code. pay attention to what you are sending to avoid annoying reboots
  • the default libogc base address for wii homebrew is at 0x80003f00. this gives a PSO compatible stub ~10k of memory. hence, the stub's main() functions was written in c so that its easy to improve/fix
  • the loader initially puts a received binary in MEM2 to avoid overlaps. it will be relocated from there. unfortunately the loader itself has a base address in MEM1. putting it in MEM2 is on my TODO list
  • for the record: you can use the trucha signer to boot this app straight from dvd, but that is currently not supported nor endorsed. do not ask about it. seriously.

thanks

  • shagkur, for helping me getting the stub working and providing the linkerscript
  • the devkitpro team
  • team tweezers for making all of this possible
  • all open source wii coders
  • nuke for sharing code for his adapter

download

v0.0.2b

geckoloader-0.0.2b.tgz

v0.0.2

geckoloader-0.0.2.tgz

changelog

  • v0.0.2b
  • fixed a timing issue in the usbgecko flash code. since i couldn't reproduce this on my setup, thanks go out to my testing bitches bLAStY and NoNameNo
  • the included client now works on osx thanks to bushing
  • added an extra checked for malformed .dol files (some doltool converted .elf's)
  • included a tiny test application
  • v0.0.2
  • first public release