I think you're conflating a lot of different things here.  I'm assuming you are running a 3rd party firmware on your device which boots SeaBIOS as its payload.  Wifi/LAN not working are unlikely to be firmware related, so flashing something else isn't going to help.  The 'update microcode' message is just that, Linux is updating your microcode as part of booting.  There's no problem which needs fixing.

Assuming the problem you are trying to solve is lack of network connectivity on your device, the best resource for that is going to be some place that  deals with hacking Chromebooks, like https://www.reddit.com/r/chrultrabook/.  But it's not a SeaBIOS issue in any way.

On Wed, Aug 22, 2018 at 10:03 AM Roberto Simonini <robertosimonini@gmail.com> wrote:
I have acer c720 with seabios and ubuntu both wifi and lan no longer work since then
I do not have the network able to flash the seabios. is there a ROM version that can be downloaded but flash without a network?
I also have the following message at startup: ...tsc-to deadline disable due to errata ...update microcode...unable to read hardware clock
grazie robrto simonini 
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