grub bootloader Configuration Changes
Before trying specific kernel boot parameters, it is advisable to first add them temporarily for testing or troubleshooting purposes. When the parameters have the intended effect, they can then be added permanently.
Kernel boot parameters are text strings that disable/enable certain features or change specific system behaviors. To achieve the desired change, note kernel boot parameters: 
- can be a simple keywords (like "
splash" or "
- are case-sensitive (for example "
Noapic" would not have any effect but "
noapic" would take effect)
- might have an
=sign to denote values (like "
- might include punctuation (""
Kernel boot parameters have no effect unless entered exactly as advised -- spelling/formatting errors or invalid values do not result in an error message.
Kernel Boot Parameter Change
Follow these steps to temporarily add kernel boot parameters. Useful for testing such a normal (non-recovery mode) boot while enabling verbose boot messages. Alternatively, if that is accessible , see Permanent Configuration Changes.
Permanent Configuration Changes
Inspect Grub Configuration Changes
1. Put folder
/boot/grub under git version control.
Git is a useful tool to record which files in a folder changed in what way.
2. Change grub configuration.
Make changes according to Permanent Configuration Changes.
3. See which files were modified by
From the same folder.
4. Inspect the changes.
Using command line using default diff viewer
diff which might be a bit difficult to read but an alternative is presented in the next step.
- Not accessible if boot is broken obviously.
- Or shut it down and power it on again.
The system might hang when holding down the
Shiftkey. If that happens, just briefly release the
Shiftkey and hold it down again until the grub menu appears.