From Newsgroup: comp.sys.raspberry-pi
Re: How to boot from SD but run from US
By: Dave Vandermeer to Dennis Slagers on Wed Feb 26 2025 17:45:00
Actually I did read somewhere that it is possible. Technically you only need to use the SD card to boot to init, so modify your /etc/fstab to change the location of your root partition to the device of the USB drive. (Theoretically, I haven't booted my Pi's in quite some time.. rapidly losing interest in running a BBS) ..
if you need to and want to know how to setup a raspi to run off a usb drive, while only booting to sd card, let me know. I can respond with instructions. I have ran my raspi using usb drive since raspi b+.
newer raspi devices are easier to setup that way, specifically if you have a newer raspi. the imager that is with the rasp os has an option for what drive to write a new image to.
I've taken my existing os on sd card, put in the usb drive I want to run off of
and wrote out everything to the usb drive, modified the boot config files and /etc/fstab, reboot to run off usb drive.
raspi b can be run this way pretty nice.
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