I tried to install a thrid-party OpenWrt image to a computer. After writing the image file to SSD and start booting, the kernel message prints at a really slow pace, although some of the timestamp seems to be normal.

Here is the result of dmesg. The printing pace is mostly of 2 seconds for one line, but the timestamp only increased few milliseconds. As it's too long I posted it to Pastebin: https://paste.ubuntu.com/p/ZJKfXfGDSk/

Is that normal? It takes me about 5 minutes to complete the whole booting process. Once it boots, it works flawlessly. Also this phenomenon won't happen when using Legacy boot mode and the booting process takes about 6 seconds before you can press enter to access the console.

  • @Johan Myréen Please add as an answer so I can select as the best answer. That's exactly what the problem is. Thanks so much.
    – whc2001
    May 22, 2019 at 14:01
  • may I ask you how you got Openwrt to boot on UEFI?
    – Mehdi
    Jun 10, 2019 at 13:35
  • @Mehdi I am using an 3rd party source and it comes with Build EFI GRUB images (Linux x86 or x86_64 host only) in the target image options. I believe there is no such option in the official source.
    – whc2001
    Jun 12, 2019 at 4:17
  • can you please provide a link to that third party source? What I found now to be efi compatible is a still open pull request in the official github repository and another version from JOW git.openwrt.org/openwrt/staging/jow.git
    – Mehdi
    Jun 12, 2019 at 9:26
  • 1
    @Mehdi Here it is: github.com/coolsnowwolf/lede
    – whc2001
    Jun 13, 2019 at 6:16

1 Answer 1


Remove console=ttyS0,115200n8r from the kernrl command line so the kernel doesn't try to write messages to the serial port, which is slowing down the boot.

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