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sw4 jumper for disabling eMMC boot / multiboot - Printable Version

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sw4 jumper for disabling eMMC boot / multiboot - ChriChri - 03-09-2020

Ran into the following: I wanted to connect a little switch to choose between sdcard and emmc boot.

Didn't work: Open was fine - eMMC booted.

But closed seemed to boot from eMMC, too, but the archlinux didn't come up and got stuck while looking for its root device.

After some fiddling around, trying and reading serial console I tried a _jumper_.

Worked. As described in the layout the jumper shortens the clock of the emmc to ground. Is it possible that already a 5cm wire has too much resistance to disable the eMMC?

And if so, is there a smarter way to multiboot?