Comment 5 for bug 1745927

There are a few steps that need to happen:
1) determine which kernel modules are required for that hardware
2) check if those kernel modules are build and available from the regular userspace package
3) check if those kernel modules are included in the udeb kernel package for the installer
4) check that installer correctly detects and loads those missing modules and/or said udebs are included in the d-i built itself.

If I am reading the provided debug output right, "cxgb4" driver is required. I see that there is

kernel/drivers/net/ethernet/chelsio/cxgb4/cxgb4.ko

built in the regular kernel build, and shipped in the -extra package.
(there are a few others as well e.g. iw_cxgb4, cxgb4i, cxgb4vf)

However, I do not see net/ethernet/chelsio/* included in the nic-modules-4.13.0-32-generic-di_4.13.0-32.35_ppc64el.udeb package as used by the installer.

Therefore I believe the scope of this bug is to make sure that net/ethernet/chelsio/* is shipped in the nic-modules udeb package.

Then a d-i rebuild will be needed.

Then the bug reporter can re-validate if this issue becomes resolved.