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i.mx6ull sd boot bus width

Question asked by David Luberger on Jul 13, 2018
Latest reply on Jul 13, 2018 by igorpadykov

I'm mostly following the EVK reference design, but I noticed in the boot config via gpio, the sd card boot setting is hard-wired for 1-bit bus width, yet off-the-shelf sd cards are 4-bit.  I read somewhere that during boot you *can* use 1-bit communication (i'm not sure why one would do that) but I don't see anywhere how the sd card peripheral then gets "put back" to 4-bit mode.  clearly the EVK works so it's happening somehow, but I'm not seeing where. Is this simply a matter of configuring in the device tree?  where and how is the boot sd card changed from 1-bit to 4-bit after boot?

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