Network issues, but worked from live image??

Trying to install 2.8.2 on a HP elitedesk. Booting from USB.

Live image gives me a working network – I can ping the outside world.
Install finds eno0, gets to "Configure the Network" eth0 network and then hangs.
Either I kill the dhcpclient, or wait ages, and it tells me something is incompatible with DHCP???

So, I say skip configuring the network, but later in the install it asks about proxy config.
I leave that blank. Then, it complains "bad archive mirror"
I go back, and say to just do the minimal install, but then it errors on 'grub-efi-amd64'

Hmmm. In this other page  forum.linuxcnc.org/9-installing-linuxcnc...-82-fails-to-install ,
tommylight suggests some BIOS changes (disable security and UEFI).
So, I do that, and the PC complains about some Physical Presence Indicator BS???
Esc out of that, attempt install again (after installing GRUB in Advanced).
It still hangs at configuring the network,
but this time when I killed the dhcpclient processes, it actually had networking!
I could ping the outside world!!!
Which means the install progresses, and I get it there in the end

I was a little alarmed that the install ISO can't actually install without an internet connection, though.
Are all releases like this? Or just the latest Debian?

Tommy, thanks for the fast reply.

Just to document the process, for other users in the future,
fresh install on an old PC (Pentium4, USB1, install was text only)...

1) I disabled serial and EtherNet in the BIOS (hoping that less interrupts means more performance : - )
2) Debian can't detect any network hardware I left the ethernet driver at "no ethernet card."
3) It installs packages, then gets to "Configure the package manager" asking about a proxy, then error-ing "Bad archive mirror."
4) Hit Esc-ape a few times
5) Say Yes to "Continue without a network mirror?"

It then eventually finishes the install.

(over time, Max Jitter approaches 500,000ns, and Last interval is usually 1,000,000ns, so not really a good candidate)