Demo unit from work with 0’s for an IMEI.

Hi, so I’ve gotten an ex demo unit from my work (SM - G989F, S20). I’ve removed the demo software and flashed a stable consumer version of One UI. Before and after flashing the IMEI was consisting of ALL 0’s. I understand this is because it was/ is a (ex)demo unit, but is there anyway I can generate a valid IMEI myself? I’ve contacted Samsung and they told me it can’t be done (by them), so my main question is: can I do it myself with certain softwares ? Thanks!