Wired has an article about some new research by Duo Security, on how OEMs build insecure laptops.
https://duo.com/blog/out-of-box-exploitation-a-security-analysis-of-oem-updaters
https://www.wired.com/2016/05/2036876/
It is a nice article, but only scratches the surface. OS-level OEM bloatware is fixable. Firwmare-level OEM bloatware is often not fixable. And in recent years, operating systems are tied to the firmware more than ever, Microsoft Windows has install binaries embedded in ACPI tables. So, read the article and realize that the situation is much worse than it mentions. 😦
Firmware Security 