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I'm attempting to get a minimal buildroot system up and running on my Raspberry Pi 3 B+ but after I've flashed the SD card, installed the card, powered up the pi, and connect an HDMI cable, I only ever get the multicolor screen with the lightning bolt.

From what I understand, I should be getting a getty prompt with the ability to login. I've followed the instructions on the buildroot GitHub page: https://github.com/buildroot/buildroot/tree/master/board/raspberrypi but with no avail. I run the following commands to build the image:

make raspberrypi3_64_defconfig

make

The result of my build contains the following files/directories: 

cm2710-rpi-3-b.dtb 
bcm2710-rpi-cm3.dtb
boot.vfat
rootfs.ext2  
rootfs.ext4
rpi-firmware 
sdcard.img 
zImage

I then flash the card with sudo dd bs=4M status=progress if=sdcard.img of=/dev/sdb

I don't see any options explicitly for the raspberry pi 3 b+, I just assumed the raspberrypi3_64_defconfig was the correct configuration.

Getting to a login screen will be a huge win for me! Thanks.

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  • do you know what the "lightning bolt" means? usually means you don't have a good power supply – Jaromanda X Jan 19 '19 at 3:05
  • @JaromandaX yes I am aware. What's interesting is I have successfully booted several other OSs with the same exact hardware setup. This makes me believe that I have done something wrong with building the image. Maybe old firmware? Not sure. – user985030 Jan 19 '19 at 3:15
  • oh ... that is interesting, not sure I can help then – Jaromanda X Jan 19 '19 at 3:24
  • Which model Rpi do you have? Your text says B+ and your tag says 3B+. And what exact command did you use? The readme lists specific commands for each board. – T. M. Jan 19 '19 at 14:36
  • @T.M. Sorry, I left off the 3. I have the RPI 3 B+ with ARM v8 A53 arch. – user985030 Jan 20 '19 at 14:21
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raspberrypi3_64_defconfig isn't even listed in the readme, I assume because it's experimental. Try 

make raspberrypi3_defconfig

That's the one listed so it should be expected to work.

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2

I figured out what my issue was. For some reason, the version of build root I pulled down didn't contain the proper files for the Pi 3 B+. These are the steps that I followed:

  1. git clone https://github.com/buildroot/buildroot.git
  2. cd buildroot
  3. make raspberrypi3_defconfig
  4. make
  5. dd bs=4M status=progress if=./output/images/sdcard.img of=/dev/sdb

I then put the card in and it booted like a champ. Now I can spend time configuring my OS with what I actually need! Yay!

To be clear, the file that I couldn't find when was this one: bcm2710-rpi-3-b-plus.dtb. That was definitely the magic sauce that caused me to fail previously. Thanks @T.M. for pointing this out to me.

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