RHEL 7 upgraded minor release but boot menu does not show newly installed kernel

I'm administering a Red Hat Enterprise Linux version 7.8 server host and just did an upgrade of minor release to version 7.9 using RHEL official ISO installation media 7.9, and rebooted after the upgrade. (Please note that is server is running on a VMware vSphere 7 virtual machine.) Now, here's the problem. The output of cat /etc/os-release showed: NAME="Red Hat Enterprise Linux Server" VERSION="7.9 (Maipo)" ID="rhel" ID_LIKE="fedora" VARIANT="Server" VARIANT_ID="server" VERSION_ID="7.9" PRETTY_NAME="Red Hat Enterprise Linux Server 7.9 (Maipo)" ANSI_COLOR="0;31" CPE_NAME="cpe:/o:redhat:enterprise_linux:7.9:GA:server" HOME_URL="https://www.redhat.com/ " BUG_REPORT_URL="https://bugzilla.redhat.com/ " REDHAT_BUGZILLA_PRODUCT="Red Hat Enterprise Linux 7" REDHAT_BUGZILLA_PRODUCT_VERSION=7.9 REDHAT_SUPPORT_PRODUCT="Red Hat Enterprise Linux" REDHAT_SUPPORT_PRODUCT_VERSION="7.9" But meanwhile the output of uname -srm showed: Linux 3.10.0-1127.el7.x86_64 x86_64 And the yum list installed kernel said there are two installed kernels, as shown below: Loaded plugins: langpacks, product-id, search-disabled-repos, subscription- : manager Installed Packages kernel.x86_64 3.10.0-1127.el7 @anaconda/7.8 kernel.x86_64 3.10.0-1160.el7 @local-iso I don't get it. Why after an upgrade and reboot, the OS still boots into version 7.8 and the version 7.9 couldn't event showed on boot menu? So, in order to troubleshoot faster, I collected some information from the OS, as listed below, which would be helpful: Output of awk -F\' '==menuentry {print i++ : }' /boot/grub2/grub.cfg: 0 : Red Hat Enterprise Linux Server (3.10.0-1127.el7.x86_64) 7.8 (Maipo) 1 : Red Hat Enterprise Linux Server (0-rescue-71be072259f245f5b1a7cc30b3746e8f) 7.8 (Maipo) Output of grub2-editenv list: saved_entry=Red Hat Enterprise Linux Server (3.10.0-1127.el7.x86_64) 7.8 (Maipo) Output of grubby --info ALL: index=0 kernel=/boot/vmlinuz-3.10.0-1127.el7.x86_64 args="ro crashkernel=auto rd.lvm.lv=rhel/root rd.lvm.lv=rhel/swap rhgb quiet LANG=en_US.UTF-8" root=/dev/mapper/rhel-root initrd=/boot/initramfs-3.10.0-1127.el7.x86_64.img title=Red Hat Enterprise Linux Server (3.10.0-1127.el7.x86_64) 7.8 (Maipo) index=1 kernel=/boot/vmlinuz-0-rescue-71be072259f245f5b1a7cc30b3746e8f args="ro crashkernel=auto rd.lvm.lv=rhel/root rd.lvm.lv=rhel/swap rhgb quiet" root=/dev/mapper/rhel-root initrd=/boot/initramfs-0-rescue-71be072259f245f5b1a7cc30b3746e8f.img title=Red Hat Enterprise Linux Server (0-rescue-71be072259f245f5b1a7cc30b3746e8f) 7.8 (Maipo) index=2 non linux entry Output of grubby --info DEFAULT: index=0 kernel=/boot/vmlinuz-3.10.0-1127.el7.x86_64 args="ro crashkernel=auto rd.lvm.lv=rhel/root rd.lvm.lv=rhel/swap rhgb quiet LANG=en_US.UTF-8" root=/dev/mapper/rhel-root initrd=/boot/initramfs-3.10.0-1127.el7.x86_64.img title=Red Hat Enterprise Linux Server (3.10.0-1127.el7.x86_64) 7.8 (Maipo) Output of lsblk: NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 150G 0 disk ├─sda1 8:1 0 2M 0 part ├─sda2 8:2 0 200M 0 part /boot └─sda3 8:3 0 149.8G 0 part ├─rhel-root 253:0 0 117.8G 0 lvm / └─rhel-swap 253:1 0 32G 0 lvm [SWAP] sdb 8:16 0 300G 0 disk └─dataVG-dataLV 253:3 0 300G 0 lvm /Data sdc 8:32 0 300G 0 disk └─bkpVG-bkpLV 253:2 0 300G 0 lvm /Backup sr0 11:0 1 1024M 0 rom Output of df -Th: Filesystem Type Size Used Avail Use% Mounted on devtmpfs devtmpfs 7.8G 0 7.8G 0% /dev tmpfs tmpfs 7.8G 8.0K 7.8G 1% /dev/shm tmpfs tmpfs 7.8G 13M 7.8G 1% /run tmpfs tmpfs 7.8G 0 7.8G 0% /sys/fs/cgroup /dev/mapper/rhel-root xfs 118G 13G 106G 11% / /dev/sda2 xfs 197M 173M 25M 88% /boot /dev/mapper/bkpVG-bkpLV xfs 300G 33M 300G 1% /Backup /dev/mapper/dataVG-dataLV xfs 300G 33M 300G 1% /Data tmpfs tmpfs 1.6G 12K 1.6G 1% /run/user/42 tmpfs tmpfs 1.6G 0 1.6G 0% /run/user/0 Output of ls /boot: config-3.10.0-1127.el7.x86_64 initramfs-0-rescue-71be072259f245f5b1a7cc30b3746e8f.img System.map-3.10.0-1127.el7.x86_64 config-3.10.0-1160.el7.x86_64 initramfs-3.10.0-1127.el7.x86_64.img System.map-3.10.0-1160.el7.x86_64 efi initramfs-3.10.0-1127.el7.x86_64kdump.img vmlinuz-0-rescue-71be072259f245f5b1a7cc30b3746e8f extlinux symvers-3.10.0-1127.el7.x86_64.gz vmlinuz-3.10.0-1127.el7.x86_64 grub2 symvers-3.10.0-1160.el7.x86_64.gz vmlinuz-3.10.0-1160.el7.x86_64 Output of ls /boot/efi/EFI/redhat/: BOOT.CSV BOOTX64.CSV fw fwupia32.efi fwupx64.efi mmx64.efi shim.efi shimx64.efi shimx64-redhat.efi ============================================================================== I tried two methods, One is executing the following 2 commands and reboot system: grub2-set-default 0 grub2-mkconfig -o /boot/grub2/grub.cfg The other one is executing the following 3 commands and reboot system: dracut -f initramfs-3.10.0-1160.el7.x86_64.img grub2-set-default 0 grub2-mkconfig -o /boot/grub2/grub.cfg Please note that the output of grub2-mkconfig -o /boot/grub2/grub.cfg is: Generating grub configuration file ... File descriptor 6 (/dev/pts/0) leaked on vgs invocation. Parent PID 3352: /usr/sbin/grub2-probe File descriptor 6 (/dev/pts/0) leaked on vgs invocation. Parent PID 3352: /usr/sbin/grub2-probe Found linux image: /boot/vmlinuz-3.10.0-1160.el7.x86_64 Found linux image: /boot/vmlinuz-3.10.0-1127.el7.x86_64 Found initrd image: /boot/initramfs-3.10.0-1127.el7.x86_64.img Found linux image: /boot/vmlinuz-0-rescue-71be072259f245f5b1a7cc30b3746e8f Found initrd image: /boot/initramfs-0-rescue-71be072259f245f5b1a7cc30b3746e8f.img File descriptor 6 (/dev/pts/0) leaked on vgs invocation. Parent PID 3651: /usr/sbin/grub2-probe File descriptor 6 (/dev/pts/0) leaked on vgs invocation. Parent PID 3651: /usr/sbin/grub2-probe done Both of these solution eventually failed to make the OS boot into system and the error messages on the screen during the boot are similar that the root fs cannot be mounted, as shown below: Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0) CPU: 1 PID: 1 Comm: swapper/0 Not tainted 3.10.0-1160.el7.x86_64 #1 Can anyone provide some tips on troubleshooting why new kernel cannot be booted please?