# Yocto removing/bypassing U-Boot dependency (i.e. only build mender-client) **URL:** \ **Category:** Yocto Project\ **Created:** [August 2, 2022, 7:05pm UTC](https://hub.mender.io/t/yocto-removing-bypassing-u-boot-dependency-i-e-only-build-mender-client/5169 "2022-08-02T19:05:06Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Kris](https://avatars.discourse-cdn.com/v4/letter/k/82dd89/32.png) [@Kris](https://hub.mender.io/u/Kris)\ **Post date:** [August 2, 2022, 7:05pm UTC](https://hub.mender.io/t/yocto-removing-bypassing-u-boot-dependency-i-e-only-build-mender-client/5169/1 "2022-08-02T19:05:06Z")
I apologize if this isn’t the right category, please feel free to move it if needed. We’re working with a customer to integrate Yocto Kirkstone with Mender on one of our platforms. Using “master-next” for a proof of concept, I wanted to make that clear just in case it is important to the issue at hand. The specific platform in question we already have a U-Boot integration for the necessary Mender variables, etc. However we did that work with Buildroot. Moving to Yocto and meta-mender, it seems _building_ U-Boot is a requirement of Mender. The U-Boot version is ancient, so much so that using newer compilers results in inexplicable issues with RAM. The U-Boot binary is booted from an embedded storage device, it is not a part of the final disk image. For all of these reasons, we need to be able to build just mender-client via Yocto. The rest of the integration is manual and should only ever be done once. Any pointers on how to either prevent Mender from trying to build U-Boot (or any bootloader) or create a dummy recipe that claims to provide U-Boot but that the meta-mender layer also doesn’t try to patch? ---
**Author:** ![Kris](https://avatars.discourse-cdn.com/v4/letter/k/82dd89/32.png) [@Kris](https://hub.mender.io/u/Kris)\ **Post date:** [August 3, 2022, 9:42pm UTC](https://hub.mender.io/t/yocto-removing-bypassing-u-boot-dependency-i-e-only-build-mender-client/5169/2 "2022-08-03T21:42:59Z")
I _think_ I have this resolved but would still love some feedback on the topic in case there is an easier route. My steps to resolve: Create a fake U-Boot package that does nothing other than exist. `cat recipes-bsp/u-boot-fake/u-boot-fake_mender.bb` ```auto DESCRIPTION = "Fake U-Boot provider" PROVIDES += "u-boot virtual/bootloader" RPROVIDES_${PN} += "u-boot virtual/bootloader" LICENSE = "MIT" MENDER_UBOOT_AUTO_CONFIGURE = "0" ``` Set this this package as providing `virtual/bootloader` and `u-boot` The current docs say it only needs to provide U-Boot, but, testing shows that `virtual/bootloader` may be more important here? `cat conf/machine/.conf` ```auto ... # Disable building u-boot IMAGE_BOOTLOADER = "" # Tricking Mender to thinking U-Boot is being built # PREFERRED_PROVIDER_u-boot = "u-boot-fake" PREFERRED_PROVIDER_virtual/bootloader = "u-boot-fake" ... ``` And I’m not sure if these are important to the equation or not, but, I did tune what specific features were enabled and disabled: `cat conf/local.conf` ```auto # Trying to tune mender features to only what we need MENDER_FEATURES_DISABLE:append = " mender-bios mender-grub mender-image-bios imender-image-gpt mender-image-ubi mender-image-uefi mender-partuuid mender-ubi mender-uboot" MENDER_FEATURES_ENABLE:append = " mender-growfs-data mender-image mender-image-sd mender-client-install mender-systemd mender-persist-systemd-machine-id" ``` ---
**Author:** ![TheYoctoJester](https://yyz2.discourse-cdn.com/flex036/user_avatar/hub.mender.io/theyoctojester/32/1444_2.png) [@TheYoctoJester](https://hub.mender.io/u/TheYoctoJester)\ **Post date:** [August 4, 2022, 1:29pm UTC](https://hub.mender.io/t/yocto-removing-bypassing-u-boot-dependency-i-e-only-build-mender-client/5169/3 "2022-08-04T13:29:13Z")
Hi @Kris! Actually (without testing, just looking at the code) there is only one place through which `mender-client` has a dependency on `u-boot`, namely [here](https://github.com/mendersoftware/meta-mender/blob/master/meta-mender-core/recipes-mender/mender-client/mender-client.inc#L111). That depends on the `packageconfig`, so if ```auto MENDER_FEATURES_DISABLE:append = " mender-uboot" ``` is set, and you make sure that your build does not add `u-boot` to the `packageconfig` (maybe hidden somewhere in an `INHERIT`, then I think it should build fine without the `u-boot` dependency. Greetz, Josedf ---
**Author:** ![Kris](https://avatars.discourse-cdn.com/v4/letter/k/82dd89/32.png) [@Kris](https://hub.mender.io/u/Kris)\ **Post date:** [August 4, 2022, 5:21pm UTC](https://hub.mender.io/t/yocto-removing-bypassing-u-boot-dependency-i-e-only-build-mender-client/5169/4 "2022-08-04T17:21:59Z")
Thanks for the info, I wish it was that easy. I may be running in to complications from other Yocto layers. Specifically NXP/Freescale layers as this is an i.MX6 device. See the error below when I remove the fake U-Boot package and removing calling out that `virtual/bootloader` is provided by it in the machine .conf: ```auto ERROR: Nothing PROVIDES 'virtual/bootloader' u-boot-variscite PROVIDES virtual/bootloader but was skipped: incompatible with machine (not in COMPATIBLE_MACHINE) u-boot-toradex PROVIDES virtual/bootloader but was skipped: Either UBOOT_MACHINE or UBOOT_CONFIG must be set in the machine configuration. u-boot-qoriq PROVIDES virtual/bootloader but was skipped: incompatible with machine (not in COMPATIBLE_MACHINE) u-boot PROVIDES virtual/bootloader but was skipped: Either UBOOT_MACHINE or UBOOT_CONFIG must be set in the machine configuration. u-boot-boundary PROVIDES virtual/bootloader but was skipped: incompatible with machine (not in COMPATIBLE_MACHINE) u-boot-qoriq PROVIDES virtual/bootloader but was skipped: incompatible with machine (not in COMPATIBLE_MACHINE) u-boot-fslc PROVIDES virtual/bootloader but was skipped: Either UBOOT_MACHINE or UBOOT_CONFIG must be set in the machine configuration. u-boot-imx PROVIDES virtual/bootloader but was skipped: Either UBOOT_MACHINE or UBOOT_CONFIG must be set in the machine configuration. u-boot-kontron PROVIDES virtual/bootloader but was skipped: incompatible with machine (not in COMPATIBLE_MACHINE) ERROR: Required build target '-image' has no buildable providers. Missing or unbuildable dependency chain was: ['-image', 'virtual/bootloader'] ``` `` and `` are customized machine and target types. Before adding Mender layers to the mix, this error did not appear and no U-Boot was ever built despite the NXP layers really wanting to build `u-boot-imx`. I’d appreciate any pointers on tracking down where this sudden dependency is coming from. I’m currently staring at `bitbake -e` to see if anything stands out. Simply grepping for `INHERIT` with `u-boot` through all of the sources doesn’t return any matches. Thanks again!