backup – Informix onunload/onload between different arch

I have some necro-project using Informix Dynamic Server Version 7.31.UD1.
I need to backup-restore database between servers. The thing is, the onload just silently exits and doesn’t create a database, giving no errors. I’ve successfully used this method on the same server to perform a backup/restore routine, so I’m almost sure I’m doing it right:

<console A>
(root@s10-zone informix)# rm -rf /tmp/.dbld                                 
(root@s10-zone informix)# mkfifo /tmp/.dbld                                 
(root@s10-zone informix)# cat /opt/oracle/exchange/perms32_unl > /tmp/.dbld

<console B>
(informix@s10-zone ~)$ onload -t /tmp/.dbld -b 100 -d default rist
Please mount tape and press Return to continue ...
<I press Enter, 2-5 seconds pass, nothing happens>

The only explanation so far is that the onunload backup was don on a i386 arch, and I’m doing onload import on an amd64 server, – am I right assuming it fails because of this ? The official documentation says “If the page sizes are different, onload fails. If the alignment or numeric data types on the two computers are different (for example, with the most significant byte as last instead of first, or different float-type representations), the contents of the data page could be misinterpreted.”, but the page size of identical (4K), not so sure about float representation though.