this works for me :- (sorry for a lengthy answer please read carefully) ! first backup your data and your essential drivers(backup is very important because in trouble and bad time may be you cannot able to do it if you use kali as dual boot or primary) if you restart it and found error then you can:- poweroff your machine (by button or unplug the cord ) >strart your machine go to > advanced options > select kali 6.6.15 (your machine starts) >(now you can backup if not taken ). try :- goto 'kali tweaks' then 'network repo.' then select 'mirrors:cloudflare' and 'protocol:HTTPS' and then 'apply' . after above , open terminal and type 'sudo apt-get update' , 'sudo apt upgrade' then you get error like this:- bad exit status 2,sub procss /usr/bin/dpkg.... etc etc.. now figure out which package intruppt with linux headers and linux images like here (look at raw output provided below) 'realtek-rtl88xxau' is cause of problem. (hey! may be your error different if yes then you need to remove that package ). this is the error so we need to fully remove it for remove :- type command 'sudo su' then 'locate *package_name* ( put stars before and after package_name and of course you need to replace package_name with your package which cause error) !!! now before removing put some common sense and do not remove any other necessary or system pacakges (you can also copy file which you delete with their path so in any trouble you can easily revert the process) now start copying the path of repos or packages and search it in your file manager ,, you can also use cli interface but gui is more simple. after removing 'dpkg --configure -a' and 'apt upgrade' if error remains same reboot and try 'dpkg --configure -a' and 'apt upgrade' if you cannot able to boot any error show then you can try:- poweroff your machine (by button or unplug the cord ) >strart your machine go to > advanced options > select kali 6.6.15 (your machine starts) and try above commands with root privilage. now error vanish. and reboot normaly and type 'hostnamectl' (in terminal) you greeted with "Kernel: Linux 6.8.11-amd64" and other stuff (raw output) for reference may be somethings different.:- "Building module: Cleaning build area... Building module(s)................(bad exit status: 2) Failed command: /usr/src/realtek-rtl8814au-5.8.5.1~git20231211.866a910/dkms-make.sh Error! Bad return status for module build on kernel: 6.8.11-amd64 (x86_64) Consult /var/lib/dkms/realtek-rtl8814au/5.8.5.1~git20231211.866a910/build/make.log for more information. Sign command: /lib/modules/6.8.11-amd64/build/scripts/sign-file Signing key: /var/lib/dkms/mok.key Public certificate (MOK): /var/lib/dkms/mok.pub Building module: Cleaning build area... Building module(s)............(bad exit status: 2) Failed command: (cutted for short answer)etc etc