9.1.0 : netinst : installs well, but useless after firstboot

[Mayuresh Kathe <mayuresh@kathe.in>]

hello,

i just installed the firmware netinst version of 9.1.0 from; 
https://cdimage.debian.org/cdimage/unofficial/non-free/cd-including-firmware/9.1.0+nonfree/amd64/iso-cd/firmware-9.1.0-amd64-netinst.iso 
and post first boot failed to get the network readily available.

the biggest problem is that my machine does not have a wired network 
interface, only wifi (which works just fine under ubuntu 17.04), and so 
can't figure out how to move ahead without having to reboot off the 
ubuntu 17.04 in "live" mode.

any help on how to proceed with setting up the network after completion 
of the install (in spite of having had setup the network during install) 
would be most welcome.

thanks,

~mayuresh