Hi wiak, yes good to find what's exactly the cause of the boot delay, instead of depending on some possible lucky coincidence.
For what it's worth:
I did some research, by using the same for loop as from Weedog Void initrd (modprobe modules) on DebianDog porteus-boot and found that if ata_piix is not at the end (or near) then booting hangs on that too.
So it seems to me that the order is important.
Other research I did was trying out replacing with other (older) version of busybox in the initrd and had better results (much smaller delay time booting Weedog Void) (but adding ata_piix as the last module was still required), e.g. very old v1.19 from here https://busybox.net/downloads/binaries/1.19.0/ (busybox-i686, is the one I tried).