How to boot linux into RAM?

Question

linux

All the best!
I have a small assembly of Linux (on ubuntu) which I recorded on a USB flash drive, and all this also works from a USB flash drive and on a USB flash drive. I have problems with electricity, and from time to time, after power surges, the flash drive fails. How to make everything loaded into RAM at startup?
I picked the file in /boot/grub/grub.cfg there after quiet splash I added toram but something didn’t help, everything disappears when the flash drive is removed ... can I look in the direction of fstab ?
Tell a newbie