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  • Booting from a different device to root. Pi 5

    From The Natural Philosopher@3:633/10 to All on Thu Aug 13 16:34:54 2026

    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)
  • From The Natural Philosopher@3:633/10 to All on Thu Aug 13 17:13:21 2026
    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� 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?



    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)
  • From John R Walliker@3:633/10 to All on Thu Aug 13 16:59:24 2026
    On 13/08/2026 16:34, The Natural Philosopher wrote:

    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?



    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)