25.5. Setting the amount of memory manually if RAM is not recognized

Procedure

1. Check the amount of memory that your system currently reports in MiB:

   $ free -m

2. Reboot your system and wait until the boot loader menu is displayed.

   If your boot timeout period is set to 0, press the Esc key to access the menu.

3. From the boot loader menu, use your cursor keys to highlight the entry you want to boot, and press the Tab key on BIOS-based systems or the e key on UEFI-based systems to edit the selected entry options.

4. In the list of options, find the kernel line: that is, the line beginning with the keyword linux. Append the following option to the end of this line:

   mem=xxM

5. Replace xx with the amount of RAM you have in MiB.
6. Press F10 or Ctrl+X to boot your system with the edited options.
7. Wait for the system to boot, log in, and open a command line.

8. Check the amount of memory that your system reports in MiB:

   $ free -m

9. If the total amount of RAM displayed by the command now matches your expectations, make the change permanent:

   # grubby --update-kernel=ALL --args="mem=xxM"