Hi, the info about converting to booting from USB is on the RPi forum, here's a quick run through.
Code:
echo program_usb_boot_mode=1 | sudo tee -a /boot/config.txt
reboot & check it was set up OK
Code:
vcgencmd otp_dump | grep 17
you should see
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Put the NBSD image onto your microSD card, & boot it up.
The NBSD image for RPi3 is in Japanese so, change the encoding in /etc/wscons.conf
then change these in your .xinitrc
Code:
export LANG=en_GB.UTF8
(Change UK & GB to what you need.)
You should now be running NBSD from microSD card.
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TinyCore Linux is another O/S that I tried out booting from USB, it loads to ram, & if I remember, wifi worked OK on it.
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P.S. Once the OTP bit is set, you can boot from microSD cards or from USB.