Some builds FTBFS on Jenkins: firmware-b43legacy-installer postinst fails to connect to downloads.openwrt.org

e.g.:

• https://jenkins.tails.boum.org/job/build_Tails_ISO_stable/6758/consoleFull (isoworker4.dragon)
• https://jenkins.tails.boum.org/job/build_Tails_ISO_20877-merge-upstream-torbrowser-launcher/1/consoleFull (isoworker3.dragon)

However other builds worked on the same isoworkers so it's not fully broken (e.g. https://jenkins.tails.boum.org/job/build_Tails_ISO_20263-test-suite-disable-spice-vdagent/33/consoleFull).

Setting up firmware-b43legacy-installer (1:019-8) ...
A chroot environment has been detected.
Remember this firmware needs kernel >= 2.6.25.
--2025-04-07 07:21:06--  https://downloads.openwrt.org/sources/wl_apsta-3.130.20.0.o
Resolving downloads.openwrt.org (downloads.openwrt.org)... 151.101.22.132, 2a04:4e42:5::644
Connecting to downloads.openwrt.org (downloads.openwrt.org)|151.101.22.132|:443... failed: Connection timed out.
Connecting to downloads.openwrt.org (downloads.openwrt.org)|2a04:4e42:5::644|:443... failed: Network is unreachable.
/var/lib/dpkg/info/firmware-b43legacy-installer.postinst: Some problem occurred during the firmware download. Please check your internet connection.
dpkg: error processing package firmware-b43legacy-installer (--configure):
 installed firmware-b43legacy-installer package post-installation script subprocess returned error exit status 1