Some questions about Ubuntu installing and kernel changing

Rancho_2508

Hi!there.
Recently I bought a UP Xtreme, but unfortunately, I got some problems with how to use it smoothly. I got the following two problems, it'd be greatly appreciated if they were solved.
the first trouble I encountered is about Ubuntu installing. After installing the Ubuntu system, it can't boot succussfully, and it enters \ the UEFI or grub instead of the system. I installed it many times and only several times I made it(for some reason I uninstalled it then).
the second is about changing the kernel. the after-sale servicer told me that I need to change the kernel of the Ubuntu system so that the maker board can perform best. however, I did exactly as the instructions !
), it failed to boot after the kernel change.
it's my first time to change the kernel of a system and I'm really confused. Hope anyone could help me figure it out.

Sincerely,

Pierre-louis Bossart

worked fine for me with direct packages install.
Instructions at https://wiki.up-community.org/Ubuntu#Install_Ubuntu_kernel_5.0.0_for_UP_Xtreme_locally_from_debian_packages_on_Ubuntu_18.04

Or copy/paste in bash:

PREFIX=https://launchpad.net/~aaeonaeu/+archive/ubuntu/upboard/+files/
wget $PREFIX/linux-headers-5.0.0-1_5.0.0-1.2~upboard4_all.deb
wget $PREFIX/linux-headers-5.0.0-1-generic_5.0.0-1.2~upboard4_amd64.deb
wget $PREFIX/linux-image-unsigned-5.0.0-1-generic_5.0.0-1.2~upboard4_amd64.deb
wget $PREFIX/linux-modules-5.0.0-1-generic_5.0.0-1.2~upboard4_amd64.deb
wget $PREFIX/linux-modules-extra-5.0.0-1-generic_5.0.0-1.2~upboard4_amd64.deb
wget $PREFIX/linux-source-5.0.0_5.0.0-1.2~upboard4_all.deb
sudo dpkg -i *.deb
sudo update-grub
sudo reboot