I have set Grub timeout is 4 sec. But sometimes, grub start to boot after 30 secs. Why? What's wrong?
51288
Cannot get grub menu to timeout (or go away)
2222
GRUB does not detect Windows
1385
How do I change the GRUB boot order?
52481
How to decrease the boot time
143622
Ubuntu doesn't boot!
5413
How can I repair grub? (How to get Ubuntu back after installing Windows?)
121308
How do I get the GRUB menu to show when starting my dual-boot system?
76571
grub error: you need to load kernel first
134374
Crazy boot and reboot times after upgrading to ubuntu 15.04 (a stop/start job is running for session c2)
74199
Boot GRUB to entry not booted to last time?
89925
What is the usual boot time on Ubuntu 16.04 LTS?
60845
Looking for the right way to rename the GRUB boot entries
23976
Long boot delay on Ubuntu loading/splash screen following regular dist-upgrade on clean SSD install (18.04)
157857
How do I boot my PC from GRUB?
136863
UNetbootin is stuck in an "Automatic boot in 10 seconds" countdown loop
48941
How is /etc/default/grub generated during installation?
9466
How to get to the GRUB menu at boot-time?