How to change kernel in 19.3 XFCE?

[Helmut]

I have a very old Pentium I 32bit laptop. It just needs to run Firefox for controlling some external equipment via GUI, and never sees the Internet.
It has Mint 19.3 in XFCE, and is running Kernel 5.4.xx
It also has a kernel 4.15 xx installed, but I would prefer to use that and purge the 5.4 kernel on this antique IBM X30 machine.

Question:
Since there is no screen to choose between kernels on startup, does somebody know how to switch kernels on startup?

[Pjotr]

You can make the Grub bootloader menu visible like this:
https://easylinuxtipsproject.blogspot.c ... .html#ID10
(item 10, 10.1 and 10.2)

Then you can boot from the older kernel (it's tucked away under the header Advanced), after which you should be able to remove the newer kernel(s).

[ThaCrip]

@ OP ; basically boot to the 4.15 kernel, then 'Update Manager > View > Linux Kernels' and remove all of the kernels newer than 4.15. then from now on when you reboot, it will remain on the 4.15 series kernel. NOTE: after all of that is done I would probably run 'sudo apt autoremove' (and answer yes (i.e. 'y')) which will remove any left over kernel junk. because I noticed if I remove a kernel in general through the Update Manager, while it's pretty much removed, there is still something like 70MB or so of left over junk per kernel I think, which that 'sudo apt autoremove' seems to get rid of.

NOTE: to boot to older kernel... reboot, then before Mint loads you press either ESC or SHIFT at the right time to bring up the boot menu, then select the 4.15 kernel. then you can follow what I mentioned above.

You can make the Grub bootloader menu visible like this:
https://easylinuxtipsproject.blogspot.c ... .html#ID10
(item 10, 10.1 and 10.2)

Then you can boot from the older kernel (it's tucked away under the header Advanced), after which you should be able to remove the newer kernel(s).

Thanks to reading that I noticed the grub command prompt does happen if someone presses ESC too many times and I never knew how to get out of it, but now I do thanks for your post there with typing 'normal'. because prior to that I would just reboot and try to get the timing right.

p.s. but from what I can tell, it seems some computers use 'SHIFT' while others use 'ESC'. like my main PC (which I bought the motherboard in May 2012) uses ESC but I think my old computer from 2006 (bought this board in March 2006), uses SHIFT to access boot menu.

[Helmut]

Thanks Pjotr! Your a true Master!
After having made the formerly invisible boot screen visible by repeated and rapid "escape", I could finally choose the desired kernel.
It booted and then I easily and simply removed the unwanted kernel via update manager.