# Stuck in uboot because of serial data input

**URL:** <https://hub.mender.io/t/stuck-in-uboot-because-of-serial-data-input/3941>\
**Category:** General Discussions\
**Created:** [July 29, 2021, 2:51pm UTC](https://hub.mender.io/t/stuck-in-uboot-because-of-serial-data-input/3941 "2021-07-29T14:51:24Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![profff](https://yyz2.discourse-cdn.com/flex036/user_avatar/hub.mender.io/profff/32/1117_2.png) [@profff](https://hub.mender.io/u/profff)\
**Post date:** [July 29, 2021, 2:51pm UTC](https://hub.mender.io/t/stuck-in-uboot-because-of-serial-data-input/3941/1 "2021-07-29T14:51:25Z")

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I’m experiencing a problem  
it looks that data coming from external device on serial0 is causing uboot to exit standard autoboot and interrupting the wall boot  
as u boot for converted mender images looks modded for mender can you please help me to set up silent boot with no boot delay in order to avoid waiting for for data on console for exiting boot sequence as explain here [https://raspberrypi.stackexchange.com/a/117951](https://raspberrypi.stackexchange.com/a/117951)  
at least just say me where I can find the mender modded Uboot repo in order to add my config inside and recompile it  
thanks a lot for you help

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**Author:** ![drewmoseley](https://yyz2.discourse-cdn.com/flex036/user_avatar/hub.mender.io/drewmoseley/32/47_2.png) [@drewmoseley](https://hub.mender.io/u/drewmoseley)\
**Post date:** [July 29, 2021, 5:10pm UTC](https://hub.mender.io/t/stuck-in-uboot-because-of-serial-data-input/3941/2 "2021-07-29T17:10:32Z")

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Hi @profff our u-boot fork [is here](https://github.com/mendersoftware/uboot-mender).

Drew

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**Author:** ![schrein](https://yyz2.discourse-cdn.com/flex036/user_avatar/hub.mender.io/schrein/32/1361_2.png) [@schrein](https://hub.mender.io/u/schrein)\
**Post date:** [September 14, 2021, 7:16am UTC](https://hub.mender.io/t/stuck-in-uboot-because-of-serial-data-input/3941/3 "2021-09-14T07:16:49Z")

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On a RPI2, I solved the uboot issue when an external device is connected on serial0 with :

```auto
fw_setenv stdin nulldev
fw_setenv stderr vidconsole
fw_setenv stdout vidconsole

```

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**Author:** ![sieger](https://avatars.discourse-cdn.com/v4/letter/s/7ea924/32.png) [@sieger](https://hub.mender.io/u/sieger)\
**Post date:** [August 29, 2023, 10:09am UTC](https://hub.mender.io/t/stuck-in-uboot-because-of-serial-data-input/3941/4 "2023-08-29T10:09:23Z")

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@schrein Sorry to resurrect an old topic but where did you put this? I’m trying to add it to a Yocto build by adding it to `MENDER_UBOOT_PRE_SETUP_COMMANDS` but that doesn’t seem to stick.

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**Author:** ![schrein](https://yyz2.discourse-cdn.com/flex036/user_avatar/hub.mender.io/schrein/32/1361_2.png) [@schrein](https://hub.mender.io/u/schrein)\
**Post date:** [August 29, 2023, 11:32am UTC](https://hub.mender.io/t/stuck-in-uboot-because-of-serial-data-input/3941/5 "2023-08-29T11:32:33Z")

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Hello @sieger,

sorry, I just ran the fw\_setenv command from the booted linux on the device. It’s was just needed for one device, i did not investigate how to fix RPI uboot inside Yocto recipe.