On Mon, 27 Jul 2026 at 13:00, Balaji Selvanathan
<[email protected]> wrote:
>
> Hi Ilias, Casey,
>
> On 7/24/2026 12:37 AM, Casey Connolly wrote:
> >
> > On 23/07/2026 18:43, Balaji Selvanathan wrote:
> >> Hi Casey,
> >>
> >> On 7/22/2026 8:19 PM, Casey Connolly wrote:
> >>> Hi Balaji,
> >>>
> >>> On 22/07/2026 11:23, Balaji Selvanathan wrote:
> >>>> Hi Casey,
> >>>>
> >>>> On 7/18/2026 4:19 PM, Casey Connolly wrote:
> >>>>> On 7/17/26 18:16, Balaji Selvanathan wrote:
> >>>>>> Hi Casey, Ilias, Simon,
> >>>>>>
> >>>>>> On 5/26/2026 7:05 PM, Casey Connolly wrote:
> >>>>>>> Hi Balaji,
> >>>>>>>
> >>>>>>> On 25/05/2026 13:24, Balaji Selvanathan wrote:
> >>>>>>>> Hi Ilias,
> >>>>>>>>
> >>>>>>>> On 5/23/2026 6:23 PM, Ilias Apalodimas wrote:
> >>>>>>>>> [...]
> >>>>>>>>>
> >>>>>>>>>>>> To support multi-image RAW capsules, we would need to:
> >>>>>>>>>>>>
> >>>>>>>>>>>> 1. Enhance mkeficapsule to create multi-image capsules?
> >>>>>>>>>>> There's an equivalent tool in EDKII that can produce a capsule
> >>>>>>>>>>> with
> >>>>>>>>>>> multiple payloads. There were also patches posted for
> >>>>>>>>>>> mkeficapsule,
> >>>>>>>>>>> but need some minor tweaks to merge them
> >>>>>>>>>> Can you please point me those patches? I did a search myself, but
> >>>>>>>>>> couldnt find those patches.
> >>>>>>>>> https://lore.kernel.org/u-boot/20240419065542.1160527-1-
> >>>>>>>>> [email protected]/
> >>>>>>>> This patch you mentioned here can create capsule with only one
> >>>>>>>> payload;
> >>>>>>>> means for multiple binaries we need to create multiple capsules. I
> >>>>>>>> have
> >>>>>>>> also asked the person who made this series to respin, but havent
> >>>>>>>> heard
> >>>>>>>> back from him.
> >>>>>>> From a quick look it seems like it would be fairly
> >>>>>>> straightforward to
> >>>>>>> extend mkeficapsule to support multiple images, the capsule header
> >>>>>>> has
> >>>>>>> an item_offset_list[] array with offsets to each image, today we just
> >>>>>>> write 1 but it shouldn't be too much of a challenge to put a loop in
> >>>>>>> here and extend the argument parsing.
> >>>>>>>
> >>>>>>> Given that we a) already use raw capsules and b) they are part of the
> >>>>>>> EFI spec, I'm gonna try and save us all some time and just put my
> >>>>>>> foot
> >>>>>>> down here. A single raw EFI capsule file can already support updating
> >>>>>>> multiple images, U-Boot already has all of the machinery for it with
> >>>>>>> the
> >>>>>>> exception of mkeficapsule but I expect that's something you can
> >>>>>>> tackle.
> >>>>>>>
> >>>>>>> The upside to this is that you will be able to build capsule files
> >>>>>>> for
> >>>>>>> updating xbl/tz/hyp/aop that can be consumed by U-Boot and edk2!
> >>>>>> Thanks for the detailed feedback.
> >>>>>>
> >>>>>> We agree — we'll drop the FIT capsule approach and move forward with
> >>>>>> RAW capsules.
> >>>>>>
> >>>>>> Here's the plan:
> >>>>>>
> >>>>>> 1. mkeficapsule tool: Extend Sughosh's multi-payload capsule series
> >>>>>> [1] to support generating multi-image capsules from a config
> >>>>>> file, so we can build a single capsule covering all the partitions
> >>>>>> we need to update.
> >>>>>> 2. U-Boot (Qualcomm): Today the Qualcomm capsule update code only
> >>>>>> supports a single firmware image (U-Boot itself) via a
> >>>>>> single-entry fw_images[] array. We'll move to a SoC-specific,
> >>>>>> multi- entry fw_images[] array (defined per board, e.g.
> >>>>>> board/qualcomm/<board>/fw_images.c), so a single capsule update
> >>>>>> flow can cover multiple firmware components — each with its own
> >>>>>> ESRT entry and FMP image_index — instead of just U-Boot.
> >>>>> No need for this, just build fw_images[] on the fly derived from the
> >>>>> partition table on the board, with an entry for each partition that
> >>>>> can be updated. You just need to add a map from partition label to
> >>>>> fw_name string, starting with the xbl/uefi/boot partitions we already
> >>>>> handle.
> >>>>>
> >>>>> The entire point of having logic here was to avoid per-board stuff, if
> >>>>> you're thinking "ah I'll do this per-board" you should immediately
> >>>>> wonder "but can we do it dynamically instead?".
> >>>>>
> >>>>> Thanks,
> >>>>> Casey
> >>>> Hi Casey, Ilias,
> >>>>
> >>>> Thanks for the pointer — agreed, building fw_images[] dynamically
> >>>> from
> >>>> the partition table is the right call, avoids per-target code entirely.
> >>> Can I talk to a human instead of an LLM please?
> >>>
> >>>> Plan:
> >>>> - Keep a fixed table mapping "partition label → fw_name + a fixed
> >>>> image index", this mapping going to be a superset list for all the Boot
> >>>> FW images supported in different Qualcomm targets.
> >>> This reads vaguely like a rephrasing of what I proposed, not clear if
> >>> you really understand it though.
> >>>
> >>>> Sample table:
> >>>>
> >>>> ┌──────────────────┬───────────────┬───────┬────────────────────────┐
> >>>> │ part_base_name │ fw_name │ index │ guid
> >>>> (fixed) │
> >>>> ├──────────────────|───────────────|───────-|───────────────────────- |
> >>>> │ xbl │ QCOM_XBL │ 1
> >>>> │ QCOM_XBL_GUID │
> >>>> │ ubootspl │ QCOM_UBOOTSPL│ 2 │
> >>>> QCOM_UBOOTSPL_GUID │
> >>>> │ uboot │ QCOM_UBOOT │ 3
> >>>> │ QCOM_UBOOT_GUID │
> >>>> └──────────────────┴───────────────┴───────┴────────────────────────┘
> >>>>
> >>>> Target-1 supports xbl and Target-2 supports ubootspl.
> >>>>
> >>>> - At boot, scan the partition table against this table. Only
> >>>> partitions actually present on that target get an fw_images[]/ESRT entry
> >>>> — nothing hardcoded per target.
> >>>>
> >>>> - The image index for each partition type stays fixed and published,
> >>>> so whoever builds a capsule (mkeficapsule) always knows which index to
> >>>> target, regardless of what's discovered at runtime.
> >>>>
> >>>> One wrinkle I want to flag: today's SetImage() path assumes
> >>>> dfu_alt_num = image_index - 1, i.e. it picks the Nth entry in
> >>>> dfu_alt_info purely by
> >>>> position. If a partition from the middle of the table is missing on a
> >>>> given target, everything after it would shift by one position and the
> >>>> wrong
> >>>> partition would get flashed — silently. Since I'd rather not touch
> >>>> that logic in common code, my plan is to keep every fixed index's
> >>>> position in
> >>>> dfu_alt_info stable by inserting a placeholder (U-Boot's existing
> >>>> virt
> >>>> DFU backend, which just no-ops) wherever a partition is absent, so the
> >>>> position
> >>>> math stays correct for everything after it. The missing partition
> >>>> itself simply won't have an fw_images[]/ESRT entry, so a capsule can't
> >>>> target it
> >>>> anyway — it'd get rejected before reaching DFU.
> >>> Skipping past this noise... Ilias probably knows better here but yes the
> >>> way dfu_alt_num is derived from ImageIndex does impose a limitation here
> >>> currently where we need to ensure the indexes always start at 1 and
> >>> count up.
> >>>
> >>> That being said, it's already quite complicated to have to maintain a
> >>> database of the indices for each board, and even more complicated when
> >>> we have boards that may or may not be using U-Boot SPL (for example).
> >>>
> >>> Having fixed ImageIndex values for each image would then seem to make
> >>> the most sense as we could just use fwu to set dfu_alt_num (or another
> >>> platform specific mechanism), however the EFI spec is clear that the
> >>> ImageIndex of EFI_FIRMWARE_IMAGE_DESCRIPTOR must be <= DescriptorCount
> >>> as returned by fmp->GetImageInfo(), so we would need to also have dummy
> >>> entries in the fw_images[] array so it doesn't really solve our problem.
> >>>
> >>> https://uefi.org/specs/UEFI/2.9_A/23_Firmware_Update_and_Reporting.html
> >>>
> >>> Currently, other than for setting dfu_alt_num, the only other place
> >>> where the image index needs to match is in efi_fmp_find() which was
> >>> added by [1] seemingly to prevent an incorrect image index in the
> >>> /capsule/ file causing dfu_alt_num to be set wrong resulting in the
> >>> wrong partition being flashed. In other words, we should be able to find
> >>> a way to safely remove this check.
> >>>
> >>> But alas, it seems like we are stuck with fmp->SetImage() being called
> >>> with the image index from the capsule file per the spec, and it is the
> >>> only way to identify the target partition without doing other hacks.
> >>>
> >>> I'd like to get some feedback from Ilias on this, since adding dummy
> >>> entries really doesn't feel like an acceptable approach to me. The only
> >>> alternatives I can think of also don't seem great... Either:
> >>>
> >>> 1. Sidestep the EFI spec by either caching data in the call to
> >>> GetImageInfo() or by assuming that the void *image pointer immediately
> >>> follows the efi_firmware_management_capsule_image_header (this is true
> >>> for us today but would be a fragile assumption to make).
> >>> 2. Use the internal image index (looked up via the image name and
> >>> type_id) as the index when calling fmp->set_image() - going against the
> >>> spec.
> >>>
> >>> It's not really clear to me what purpose the ImageIndex property serves,
> >>> since GetImageInfo() is meant to match on the ImageTypeId anyway, I
> >>> assume it relates somehow to the fact that there can be multiple
> >>> instances of the firmware management protocol, but in U-Boot we only
> >>> have one.
> >>>
> >>> I think the other way forward would be to use the only included escape
> >>> hatch in the UEFI spec with a custom GUID in the capsule header
> >>> capsule_guid field which would let us have a custom mechanism which in
> >>> our case could just be a soft-fork of the existing spec with minor
> >>> changes so we can just remove/ignore the UpdateImageIndex field in the
> >>> capsule. Maybe this would be the most correct solution?
> >>>
> >>> Hopefully Ilias has some time to chime in on this, I'm sure we can find
> >>> a way to go about this that doesn't involve exposing dummy data.
> >>>
> >>> Thanks,
> >>> // Casey
> >> I feel we are complicating it by trying to go for dynamic fw_images.
> >>
> >> Rather than introducing a solution that diverges from the UEFI
> >> specification, shall we use a board-specific static fw_images[]
> > Well, the solution I proposed at the end very much doesn't diverge from
> > the spec, that was kinda the point.
> >
> >> definition. This approach is simpler, remains spec-compliant, and other
> > Simpler for you to implement or simpler to maintain? I think that's
> > quite debatable...
> >
> >> vendors (like NXP, TI) have also implemented static fw_images (in board/
> >> nxp, board/ti).
> > The decision not to do this for mach-snapdragon was quite intentional
> > and was the motivator behind dynamic generation of image GUIDs:
> > https://lore.kernel.org/u-boot/[email protected]/
> >
> > The image index issue was always bound to come up, and it's absolutely
> > something we should be solving and not just sidestepping. We already
> > support dynamic fw_images[] anyway and it's already being used by some
> > devices, so we need to maintain the existing support regardless.
> >
> > As I understand it, Qualcomm also intend to support multiple boot media
> > (UFS, eMMC, SPI flash) with a single U-Boot binary, so to some extent
> > this array must be dynamic. And since at boot time we have all the info
> > we need to generate fw_images, keeping a static list per-board is at
> > best lazy and at worst will just make things even more complicated when
> > we suddenly want to support configurations with/without OP-TEE and
> > with/without SPL.
> >
> > So unless I'm missing something here I think there's a strong case here
> > to add support for ignoring the capsule provided image index, but we'll
> > see what Ilias has to say when he's back from vacation.
>
> Okay Casey.
>
> Hi Ilias,
>
> Request your input on this.
So the problem you are trying to fix here, is that you have boards
with multiple configurations, that their image index might change, but
you want to update them with a single capsule right?
If that's the case, we can have a board specific function that does
nothing by default, but on the qualcomm case, re-arranges the capsule
image indexes *after* the capsule authentication has passed. I think
this still violates the EFI spec, but I am ok with it.
Cheers
/Ilias
>
> Regards,
>
> Balaji
>
> >
> >> Regards,
> >>
> >> Balaji
> >>
> >>> [1]: 7cf06f09cc51 ("capsule: Put a check for image index before the
> >>> update")
> >>>
> >>>> Let me know if this approach sounds reasonable.
> >>>>
> >>>> Thanks,
> >>>> Balaji
> >>>>>> Will send an updated series once the mkeficapsule and qcom capsule
> >>>>>> update changes are in shape.
> >>>>>>
> >>>>>> [1] https://lore.kernel.org/u-boot/20240419065542.1160527-1-
> >>>>>> [email protected]/
> >>>>>>
> >>>>>> Regards,
> >>>>>> Balaji
> >>>>>>> Kind regards,
