Booting Pi operating system from a USB HDD partition

[paulunderwood]

This is not urgent. To put the OS onto a Pi is usually done by flashing an SD card and popping it into the Pi. I can dd the image file to a partition of my USB HDD -- the same would apply to an SSD -- but how do I install the bootloader onto the HDD (or SSD)? I can do it with grub install from the Pi OS when it is running, but first I need to boot it

I guess one way would be to boot an SD card with Pi OS on it and then run grub-install with the HDD-boot sector as the target and for the kernel and ramfs on the partition specified.

[chalsall]

Originally Posted by paulunderwood

This is not urgent.

Thanks for this Paul.

I've had similar thoughts in my head on this subject domain. Ever since Mike brought forward that there's a new "Image" for Pi's already deployed (and those we will soon have in our hands)...

Let's collaborate on this. Working together works better.

Seriously.

[paulunderwood]

Originally Posted by chalsall

Let's collaborate on this. Working together works better.

It sure does!

I now think I can skip flashing an SD card and use the (AMD/Intel) flashing computer to run grub-install with the USB HDD boot sector as a target and specify that the partition has vmlinuz and initramfs. But what happened to the boot sector of the image? Is that put onto the beginning of the partition?

[paulunderwood]

Another method is to install to an SD card and rsync its already formatted partitions to the USB partitions. Then make a few changes to /etc/fstab on the USB copy.. Run grub-install on a file which has been appropriately modified. Untested!

But I can use USB3 on my Odroid N2 -- my Pi 3B+ has only USB2. The N2 has a physical switch that boots petitboot on the SPI flash memory. So after rysnc'ing the OS from the SD card to the already formatted USB partition(s) and changing /etc/fstab on it appropriately, switch to SPI and boot via petitboot. Untested!

[chalsall]

Originally Posted by paulunderwood

Another method...

No time. But observing with interest.

Have "kit" to play with. But time is a limited resource...

Edit: Actually... To share... I've been doing a *lot* of rsync'ing recently.

Edit.PS: DD is also something to make friends with.

Edit.PPS: ddrescue as well. When your clients don't follow your backup instructions, and the "kit" is not cooperating...

[lalera]

hi,
you can try this
https://www.tomshardware.com/how-to/...berry-pi-4-usb

[paulunderwood]

Originally Posted by lalera

hi,
you can try this
https://www.tomshardware.com/how-to/...berry-pi-4-usb

That's a nice graphical way of doing it, but I am unsure that before copying the OS you can select /dev/sdaX. I don't want the other partitions to be destroyed. It seems to be, after a firmware update on Pi 4 or Pi 400, put GRUB onto the USB HDD/SDD and copy the files for the rest across. I notice the linked article does not say anything about Pi 3B+ -- I'll be using an Odroid N2 anyway.