I downloaded firmware-9.6.0-amd64-netinst.iso and successfully installed a minimal debian stretch on my UEFI/GPT disk. I then I replaced all references to "stretch" with "testing" in /etc/apt/sources.list and executed sudo apt update; sudo apt install gnome-core firefox-esr. Everything works as expected but I have the following questions which I posted on the debian-testing mailing list. Since no-one answered, I thought I would try here -
1. according to uname -r, I am running 4.9.0-7-amd64 which appears to be the stretch kernel. Is it safe to run the stretch kernel with programs / apps / utilities from testing?
2. I noticed the intel-microcode package is not installed. If I install it, could this testing version conflict with the stretch kernel?
3. Last time I tried apt upgrade, my grub menu was replaced with the grub command prompted. If there any way to avoid this happening again?