pas de demarrage sur nouveau kernel

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Hello.
I updated Ubuntu desktop 20.04 but the boot is still done on an old kernel (5 3..38 instead of 5 4..26)
is that bad? And for how long?.
Thank you for your reply.

sat

If you hold SHIFT at boot can you select the new kernel.

I can select the new kernel but nothing happens

For diagnostic purposes please provide the output that you receive for the following commands:

uname -a
lsb_release -crid
sudo apt update
sudo dpkg --audit
ls -l /boot
dpkg -l | grep ' linux-'

uname -a
Linux sam-Inspiron-15-3567 5.0.0-38-generic #41-Ubuntu SMP Tue Dec 3 00:27:35 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

lsb_release -crid
Distributor ID: Ubuntu
Description: Ubuntu 20.04 LTS
Release: 20.04
Codename: focal

ls -l /boot
total 339408
-rw-r--r-- 1 root root 224496 déc. 2 20:25 config-5.0.0-38-generic
-rw-r--r-- 1 root root 237718 avril 20 18:33 config-5.4.0-26-generic
-rw-r--r-- 1 root root 237778 avril 20 18:33 config-5.4.0-26-lowlatency
-rw-r--r-- 1 root root 237718 avril 22 16:08 config-5.4.0-28-generic
-rw-r--r-- 1 root root 237778 avril 22 16:08 config-5.4.0-28-lowlatency
drwx------ 3 root root 4096 janv. 1 1970 efi
drwxr-xr-x 6 root root 4096 mai 2 18:51 grub
lrwxrwxrwx 1 root root 30 avril 29 10:13 initrd.img -> initrd.img-5.4.0-28-lowlatency
-rw-r--r-- 1 root root 51805289 avril 26 00:13 initrd.img-5.0.0-38-generic
-rw-r--r-- 1 root root 53752949 avril 26 03:42 initrd.img-5.4.0-26-generic
-rw-r--r-- 1 root root 53751881 avril 26 03:42 initrd.img-5.4.0-26-lowlatency
-rw-r--r-- 1 root root 53753118 avril 29 10:15 initrd.img-5.4.0-28-generic
-rw-r--r-- 1 root root 53752420 avril 29 10:17 initrd.img-5.4.0-28-lowlatency
-rw-r--r-- 1 root root 182704 févr. 14 00:09 memtest86+.bin
-rw-r--r-- 1 root root 184380 févr. 14 00:09 memtest86+.elf
-rw-r--r-- 1 root root 184884 févr. 14 00:09 memtest86+_multiboot.bin
-rw------- 1 root root 4442280 déc. 2 20:25 System.map-5.0.0-38-generic
-rw------- 1 root root 4736015 avril 20 18:33 System.map-5.4.0-26-generic
-rw------- 1 root root 4737414 avril 20 18:33 System.map-5.4.0-26-lowlatency
-rw------- 1 root root 4736015 avril 22 16:08 System.map-5.4.0-28-generic
-rw------- 1 root root 4737414 avril 22 16:08 System.map-5.4.0-28-lowlatency
lrwxrwxrwx 1 root root 27 avril 29 10:13 vmlinuz -> vmlinuz-5.4.0-28-lowlatency
-rw------- 1 root root 8802040 déc. 2 20:25 vmlinuz-5.0.0-38-generic
-rw------- 1 root root 11657976 avril 20 18:41 vmlinuz-5.4.0-26-generic
-rw------- 1 root root 11707128 avril 20 18:41 vmlinuz-5.4.0-26-lowlatency
-rw------- 1 root root 11657976 avril 22 16:43 vmlinuz-5.4.0-28-generic
-rw------- 1 root root 11707128 avril 22 16:43 vmlinuz-5.4.0-28-lowlatency
lrwxrwxrwx 1 root root 24 avril 29 10:13 vmlinuz.old -> vmlinuz-5.4.0-28-generic

dpkg -l | grep ' linux-'
ii linux-aws-tools-5.4.0-1009 5.4.0-1009.9 amd64 Linux kernel version specific tools for version 5.4.0-1009
ii linux-base 4.5ubuntu3 all Linux image base package
ii linux-firmware 1.187 all Firmware for Linux kernel drivers
ii linux-generic 5.4.0.28.33 amd64 Complete Generic Linux kernel and headers
ii linux-headers-5.0.0-38 5.0.0-38.41 all Header files related to Linux kernel version 5.0.0
ii linux-headers-5.0.0-38-generic 5.0.0-38.41 amd64 Linux kernel headers for version 5.0.0 on 64 bit x86 SMP
ii linux-headers-5.4.0-26 5.4.0-26.30 all Header files related to Linux kernel version 5.4.0
ii linux-headers-5.4.0-26-generic 5.4.0-26.30 amd64 Linux kernel headers for version 5.4.0 on 64 bit x86 SMP
ii linux-headers-5.4.0-28 5.4.0-28.32 all Header files related to Linux kernel version 5.4.0
ii linux-headers-5.4.0-28-generic 5.4.0-28.32 amd64 Linux kernel headers for version 5.4.0 on 64 bit x86 SMP
ii linux-headers-generic 5.4.0.28.33 amd64 Generic Linux kernel headers
ii linux-image-5.0.0-38-generic 5.0.0-38.41 amd64 Signed kernel image generic
ii linux-image-5.4.0-26-generic 5.4.0-26.30 amd64 Signed kernel image generic
ii linux-image-5.4.0-26-lowlatency 5.4.0-26.30 amd64 Signed kernel image lowlatency
ii linux-image-5.4.0-28-generic 5.4.0-28.32 amd64 Signed kernel image generic
ii linux-image-5.4.0-28-lowlatency 5.4.0-28.32 amd64 Signed kernel image lowlatency
ii linux-image-generic 5.4.0.28.33 amd64 Generic Linux kernel image
ii linux-image-lowlatency 5.4.0.28.33 amd64 lowlatency Linux kernel image
ii linux-libc-dev:amd64 5.4.0-28.32 amd64 Linux Kernel Headers for development
ii linux-modules-5.0.0-38-generic 5.0.0-38.41 amd64 Linux kernel extra modules for version 5.0.0 on 64 bit x86 SMP
ii linux-modules-5.4.0-26-generic 5.4.0-26.30 amd64 Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
ii linux-modules-5.4.0-26-lowlatency 5.4.0-26.30 amd64 Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
ii linux-modules-5.4.0-28-generic 5.4.0-28.32 amd64 Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
ii linux-modules-5.4.0-28-lowlatency 5.4.0-28.32 amd64 Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
ii linux-modules-extra-5.0.0-38-generic 5.0.0-38.41 amd64 Linux kernel extra modules for version 5.0.0 on 64 bit x86 SMP
ii linux-modules-extra-5.4.0-26-generic 5.4.0-26.30 amd64 Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
ii linux-modules-extra-5.4.0-28-generic 5.4.0-28.32 amd64 Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
ii linux-sound-base 1.0.25+dfsg-0ubuntu5 all base package for ALSA and OSS sound systems
ii linux-source 5.4.0.28.33 all Linux kernel source with Ubuntu patches
ii linux-source-5.4.0 5.4.0-28.32 all Linux kernel source for version 5.4.0 with Ubuntu patches
ii linux-tools-5.4.0-26 5.4.0-26.30 amd64 Linux kernel version specific tools for version 5.4.0-26
ii linux-tools-5.4.0-26-generic 5.4.0-26.30 amd64 Linux kernel version specific tools for version 5.4.0-26
ii linux-tools-5.4.0-26-lowlatency 5.4.0-26.30 amd64 Linux kernel version specific tools for version 5.4.0-26
ii linux-tools-common 5.4.0-28.32 all Linux kernel version specific tools for version 5.4.0

"I can select the new kernel but nothing happens"

What exactly happens when you select the kernel 5.4.0-26-generic from the grub menu (by navigaing with the keyboard)?
It is not possible that "nothing" happens.

It says ...ramdisk .. and I could stay for 10 minutes and nothing happens. Should I try to sae the home and reinstall 20.04 - that I have upgraded from 19.10 (very messy release)?

Before you start with a new install, you could try reinstalling only the kernel packages.

Run the command

sudo apt install --reinstall linux-image-5.4.0-28-generic linux-modules-5.4.0-28-generic linux-modules-extra-5.4.0-28-generic linux-tools-5.4.0-28-generic

and reboot.
Does the 5.4.0-28 kernel work then?

Hello Manfred.
Thanks for trying helping me. Too late. I needed to reinstall a clean Ubuntu.
Everything works but the booting that I had to put in legacy boot.. I think I forgot something while installing.
Good day to you .
Closed matter