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biskeydump License

Dumps all your Switch BIS keys for eMMC contents decryption, to be used with fusée gelée (the bootrom RCM exploit)

With all your BIS keys and your RawNand.bin (or the physical eMMC attached via microSD reader or using a mass storage gadget mode in u-boot/linux) you can explore/modify your eMMC partitions using my HacDiskMount tool (if running Windows) from


  1. Build biskeydump.bin using make from the repository root directory, or download a binary release from
  2. Send the biskeydump.bin to your Switch running in RCM mode via a fusee-launcher (sudo ./ biskeydump.bin or just drag and drop it onto TegraRcmSmash.exe on Windows)
  3. Either read out and note down the text printed on your Switch's screen, or scan the generated QR code with your phone to have a copy of all your device-specific keys
  4. Alternatively, use TegraRcmSmash 1.1.0 or newer with a dummy argument so it keeps listening for usb comms, and you will get all the keys inside the console window, sample cmdline: TegraRcmSmash.exe -w out/biskeydump.bin BOOT:0x0


This section is required by the GPLv2 license

  • initial code based on
  • everything except fusee-primary and key_derivation/masterkey/exocfg from fusee-secondary has been removed (from Atmosphere)
  • all hwinit code has been replaced by the updated versions from
  • tsec.c has been slightly modified (to just use the passed-in address directly as DMA source, instead of copying to a temporary buffer)
  • qrcodegen (from has been included so that a QR code image of the dumped data can be displayed
  • main.c has been modified to get tsec fw, query for tsec key then call key_derivation.c functions using that key, then dump device and bis keys
  • key_derivation.c has been modified to use passed-in tsec key and not do any masterkey derivation


I am not responsible for anything, including dead switches, loss of life, or total nuclear annihilation.


fusee payload that dumps your BIS keys




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