The package is optional because it is not required on a VM for instance. If you read the output of the apt-get remove crda command you will notice it is proposing to remove the larger part of your kernel (linux- image-extra) which contains all of your hardware drivers, and explains the panic on next boot:
$ sudo apt-get remove crda [sudo] password for mru: Reading package lists... Done Building dependency tree Reading state information... Done The following extra packages will be installed: crda:i386 gcc-4.9-base:i386 libc6:i386 libgcc1:i386 libnl-3-200:i386 libnl-genl-3-200:i386 libssl1.0.0:i386 wireless-crda Suggested packages: glibc-doc:i386 locales:i386 The following packages will be REMOVED crda linux-generic linux-image-extra-3.13.0-36-generic linux-image-generic The following NEW packages will be installed crda:i386 gcc-4.9-base:i386 libc6:i386 libgcc1:i386 libnl-3-200:i386 libnl-genl-3-200:i386 libssl1.0.0:i386 wireless-crda 0 to upgrade, 8 to newly install, 4 to remove and 0 not to upgrade. Need to get 4,922 kB of archives. After this operation, 139 MB disk space will be freed. Do you want to continue? [Y/n] n $ If you have an older kernel installed you should be able to boot into grub (hold shift during very early boot) and select the older kernel. >From there you should be able reinstall the kernel "apt-get install linux-image-generic". -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1376809 Title: Kernel Panic After Removing Package crda To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/crda/+bug/1376809/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs