Aim:

To use up some nice SATA SSDS on a pi5.

The problem:

A Pi 5 doesn't support SATA without additional hardware.

So I have selected this: https://suptronics.com/Raspberrypi/Storage/x1009-v1.1_software.html ... ...SATA hat.

Unfortunately the SATA drives won't be available until [some part] of
the boot sequence is completed.

Now I don't mind having the /boot partition on an SD but I really don't
want the root file system there.

So I would like to force the pi to use [part of] one of the SATA drives
as rootfs.

Opinions vary on whether this is possible,

Some say just put the right device [ssd root partition] in cmdline.taxt
Others imply that you also need to compile a kernel with static pci
support because pci isn't available when the kernel is trying to load
the rootfs
Others declare it is in fact completely impossible...

I *could* fall back to a USB connected SSD to run the root system and
boot from.

Anyone know the truth, or otherwise?



--
The New Left are the people they warned you about.

--- PyGate Linux v1.5.19
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 13/08/2026 16:59, John R Walliker wrote:

On 13/08/2026 16:34, The Natural Philosopher wrote:

Aim:

To use up some nice SATA SSDSÿ on a pi5.

The problem:

A Pi 5 doesn't support SATA without additional hardware.

So I have selected this:
https://suptronics.com/Raspberrypi/Storage/x1009-v1.1_software.htmlÿ ...
...SATA hat.

Unfortunately the SATA drives won't be available until [some part] of
the boot sequence is completed.

Now I don't mind having the /boot partition on an SD but I really
don't want the root file system there.

So I would like to force the pi to use [part of] one of the SATA
drives as rootfs.

Opinions vary on whether this is possible,

Some say just put the right device [ssd root partition] in cmdline.taxt
Others imply that you also need to compile a kernel with static pci
support because pci isn't available when the kernel is trying to load
the rootfs
Others declare it is in fact completely impossible...

I *could* fall back to a USB connected SSD to run the root system and
boot from.

Anyone know the truth, or otherwise?

pci-e must be supported early in the boot sequence because
I have a couple of PI5s which boot from nvme flash.

Yes, I discovered that... I just don't know if that means it will boot
from SATA over pcie

Most people say not

John

--
?Puritanism: The haunting fear that someone, somewhere, may be happy.?

H.L. Mencken, A Mencken Chrestomathy


--- PyGate Linux v1.5.19
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 13/08/2026 16:34, The Natural Philosopher wrote:

Aim:

To use up some nice SATA SSDSÿ on a pi5.

The problem:

A Pi 5 doesn't support SATA without additional hardware.

So I have selected this: https://suptronics.com/Raspberrypi/Storage/x1009-v1.1_software.htmlÿ ... ...SATA hat.

Unfortunately the SATA drives won't be available until [some part] of
the boot sequence is completed.

Now I don't mind having the /boot partition on an SD but I really don't
want the root file system there.

So I would like to force the pi to use [part of] one of the SATA drives
as rootfs.

Opinions vary on whether this is possible,

Some say just put the right device [ssd root partition] in cmdline.taxt Others imply that you also need to compile a kernel with static pci
support because pci isn't available when the kernel is trying to load
the rootfs
Others declare it is in fact completely impossible...

I *could* fall back to a USB connected SSD to run the root system and
boot from.

Anyone know the truth, or otherwise?

pci-e must be supported early in the boot sequence because
I have a couple of PI5s which boot from nvme flash.
John


--- PyGate Linux v1.5.19
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)