Hi!
Unfortunately not yet.
The two devices are still lying next to me.
Unfortunately I'm not a Linux expert when it comes to installing OpenWrt on certain storage regions.
I was hoping that someone here in the forum would have an idea.
In the meantime, I've even got my hands on two Sophos XGS 3300s, but even there OpenWrt can only be used to a very limited extent.
An installation on the USB stick would certainly be possible and by adjusting the boot order, booting would not be a big problem, but it would not be a good solution for me.
A modified OpenWrt is already running on the devices, so it should be possible to install OpenWrt somehow.
In the meantime, the CPU is already being desoldered here to find out a little more about the board: