If you are looking at picking up a Nintendo Swich for the purpose of installing a boot loader so you can play with the NVIDIA Tegra inside you might want to look for a used model.  Nintendo have patched the ROM on new devices to block USB recovery mode overflow errors and coldboot exploits such as Fusée Gelée, preventing you from unapproved entertainment.  Ars Technica offers details on the software versions which will prevent loading your own code, as well as the theory that the new Mariko Tegra may be preventing this at a hardware level in the newest devices.

"These boot-ROM iPatches are relatively simple for Nintendo to implement in the factory when the system is manufactured, but they are impossible to load onto the tens of millions of Switch units that had already been sold before the exploit was made public."

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