Grub boot window disappeared

After a recent major update the usual boot / grub window disappeared (the window, where i can opt for the kernel to boot in or recovery mode, for example). How will i get that back?

Some info about my machine:

System:    Host: i3iMac Kernel: 5.4.89-1-MANJARO x86_64 bits: 64 Desktop: i3 4.19 
       Distro: Manjaro Linux 
Machine:   Type: Desktop System: Apple product: iMac14,1 v: 1.0 serial: <superuser required> 
       Mobo: Apple model: Mac-031B6874CF7F642A v: iMac14,1 serial: <superuser required> 
       UEFI: Apple v: IM141.88Z.0118.B12.1509081313 date: 09/08/2015 
CPU:       Info: Quad Core model: Intel Core i5-4570R bits: 64 type: MCP L2 cache: 4 MiB 
       Speed: 998 MHz min/max: 800/3200 MHz Core speeds (MHz): 1: 998 2: 998 3: 998 4: 998 
Graphics:  Device-1: Intel driver: i915 v: kernel´

You should check if you can make appear de GRUB menu when the system boots, by pressing a key depending wether you have BIOS or UEFI. I think for UEFI the correct key is ESC; in that case, boot your system an hold esc to access the grub menu, where you should be able to see the boot options and the kernels that you have installed on your computer.
Furthermore, you can always check your grub configuration file with

$ sudo mousepad /etc/default/grub

There are various options available, for example, if you want to always show the menu when system boots you should modify your file by writing

GRUB_TIMEOUT_STYLE=menu

If you want to, as said above, to press the esc key to show menu on boot, leave as:

GRUB_TIMEOUT_STYLE=hidden

Finally, if you ever make changes on GRUB configuration file, always run the command

$ sudo grub-mkconfig -o /boot/grub/grub.cfg

This will actualize the boot settings.

Try updating the grub.

$ sudo update-grub

Ok, thanks, i understand.

BUT, i’m afraid it’s another problem: When booting up i get a msg, something like: root filesystem could not be mounted read/write (it’s passing by so fast i cannot read it precisely - and i do not know where to find this error msg in journalctl. Thanks a lot in advance for any pointer.

PS. From usb boot repair i checked by xfs_repair and so far all seem fine … but the error persists.

I found the solution here. Obviously in the last big update the grub config was changed since there also disappeared the manjaro theme in grub and also grub was set to “quiet” - which i did NOT have … Anyway, all’s fine now. And thanks to you for helping out!