Troubleshooting update issues: when things don’t go as planned
Of course, nothing is perfect, and sometimes an update will fail or your computer will not work as expected after the update.
Recovery mode
If the hardware doesn’t work as expected after a software update, for example, WiFi doesn’t function, you can reboot into the previous kernel. To do this, you must use the boot manager to select the last kernel at boot. Ubuntu’s boot manager is GRUB, which can be accessed during boot by pressing the Esc or Shift key while the BIOS screen is shown. For example, this might be the screen that shows your manufacturer’s logo early in the boot process. You can tap and hold the appropriate key during that screen. If your system uses UEFI boot, it will be the Esc key; if it’s using legacy boot, it will be the Shift key.
The GRUB boot manager screen provides a menu of kernels or boot modes, which could also include other operating systems...
