From
https://www.debian.org/CD/faq/index.en.html#nonfree
What’s the difference between official and unofficial images?
Official images are built by a member of the Debian CD team and have undergone some testing to ensure they work. Once they have been released, the images never change - if they turn out to be broken, a new set with a different version number is released.
Unofficial images can be built by anyone - CD team members, other Debian developers or even advanced Debian users. Typically, they are more up-to-date, but have received less testing. Some have new features (e.g. installation support for new hardware), or contain additional software packages which are not part of the Debian archive.
你使用的nonfree ISO来自
https://cdimage.debian.org/cdimage/unofficial/non-free/cd-including-firmware/10.9.0-live+nonfree/
它是Debian Live Team制作的，但是它不属于正式的Debian ISO，对于它没有完全的支持。
此外，比较一个nonfree的Live和一个free的DVD有些奇怪。如果想要对比nonfree和free，最好选择相同的条件，例如同样是DVD或同样是Live。事实上，我倾向于Live系统的安装程序Calamares 安装程序存在问题，我在虚拟机中实验free Live时一样出现了很多问题。最好使用DVD而不是Live来安装系统。
PS:我不建议把这种含有firmware的ISO称为“非官方”，因为它们仍然是由官方的Debian 开发人员制作的。Debian 将其称为“unofficial”的意思是，虽然它们由官方的Debian 开发人员制作(并且可以在Debian的服务器上下载)，但是它们不属于Debian的一部分，因为Debian是100%的自由软件。