From Newsgroup: comp.sys.raspberry-pi

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

Aim:

To use up some nice SATA SSDS-a 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-a ... ...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

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From Newsgroup: comp.sys.raspberry-pi

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 SSDS-a 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-a ...
...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

--
rCLPuritanism: The haunting fear that someone, somewhere, may be happy.rCY

H.L. Mencken, A Mencken Chrestomathy

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From Newsgroup: comp.sys.raspberry-pi

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

Aim:

To use up some nice SATA SSDS-a 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-a ... ...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.

The Pi 5 will boot from a NVMe or USB attached SATA drive with no SD
card present. I suspect this would also be the case for a drive used
with a SATA hat. All done by the Pi 5's "BIOS", no need to compile a kernel.

A good SATA SSD with USB to SATA adaptors will give about half the
performance of a NVMe attached drive with the Pi 5 set to use PCIe 3.
I'd guess a SATA hat would be somewhere between USB and PCIe 2 speeds.

---druck
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