Unlocking without network takes a long time

[shai8I]

What's expected: After the disk unlocks, the system starts booting immediately, regardless of whether network is available.

What actually happens: Without network, it takes about 62 seconds (from the time the disk unlocks) for the system to actually start booting. (With network, it starts booting immediately.)

Reason for issue: My 'host' device is off sometimes.

P.s. Thanks for the clear guide.

[ViRb3]

Is this with WiFi or over Ethernet?

[shai8I]

Is this with WiFi or over Ethernet?

It's over USB keyboard and without Ethernet. (I've not set up the WiFi.)

[ViRb3]

Sorry, I meant when you say that it works immediately with network, is that WiFi or Ethernet?

[shai8I]

It works immediately with Ethernet plugged in.

[shai8I]

Hi @ViRb3, thanks for your efforts in addressing the issue. I wanted to let you know that I found a solution.

Solution

Edit /usr/share/initramfs-tools/scripts/init-bottom/dropbear and reduce the timeout:

# Original
DROPBEAR_SHUTDOWN_TIMEOUT=60
# Replace with:
DROPBEAR_SHUTDOWN_TIMEOUT=3

I haven't figured out how to apply this change immediately, but it works after a major system update. Additionally, I haven't tested it with SSH yet.

Tested latest image

I'm glad to report that the guide works with the latest image (Raspberry Pi OS Lite 64-bit 2024-03-15).

The solution can be applied immediately from the latest image:

1. Follow the guide using the latest image (note the new kernel version).
2. Apply the solution and run sudo apt full-upgrade.
3. The system now unlocks quickly without network.

Thanks again for taking the time to write the guide. If there's anything else I can help with, please let me know.

[ViRb3]

Glad you found a workaround. I did some searching, and this appears to be a bug with dropbear since at least 2020: https://groups.google.com/g/linux.debian.bugs.dist/c/8Yt_Kkc-DzQ

The author in the link above suggests another fix, but I honestly think yours is better given the circumstances. Will leave this open if/until somebody provides a better solution.