Comment 138 for bug 1325801

@sudodus, thanks for the test.

So the new case is "burn iso for arch A on a arch B host, where A, B can be i386 or amd64, and A != B". For this case I think there could be several different solution:

a) do not attempt to install the target syslinux if host arch != target arch. this will only prevent the popup error, however the generated usbstick will still not work

b) attempt to install the target syslinux in a chroot environment. this will work when burning an i386 image on an amd64 host, but still won't work when burning an amd64 image on an i386 host.

c) similar to method b), but also put the qemu-ARCH-static binary in the chroot so it will also work when burning an amd64 image on i386 host.

personally I have tested solution b) in my side (amd64, 15.04) with below target ISO images:

* ubuntu-13.10-desktop-amd64.iso, ubuntu-14.04.2-desktop-amd64.iso, ubuntu-14.04.2-desktop-i386.iso, ubuntu-14.10-desktop-amd64.iso, ubuntu-15.04-desktop-amd64.iso: no error during burning, can boot into the syslinux with the usbstick successfully
* ubuntu-14.04.2-server-amd64.iso, xubuntu-14.10-desktop-amd64.iso: no error during burning, can't boot into the syslinux since there is no syslinux pre-installed in the squashfs
* debian-7.7.0-amd64-netinst.iso: no error during burning, can't boot into the syslinux since there is no squashfs at all

so the behavior are all as expected.

Here is my patch:
https://code.launchpad.net/~yuningdodo/usb-creator/usb-creator.lp1325801v4-exec-syslinux-in-chroot/+merge/258346