If it helps, here’s the output from mhwd-kernel -i linux513:
[onyx ~]# mhwd-kernel -i linux513
:: Synchronizing package databases...
core 169.6 KiB 796 KiB/s 00:00 [#######################################] 100%
extra 1892.8 KiB 13.2 MiB/s 00:00 [#######################################] 100%
community 6.6 MiB 38.1 MiB/s 00:00 [#######################################] 100%
multilib 174.6 KiB 4.61 MiB/s 00:00 [#######################################] 100%
warning: linux513-5.13.13-1 is up to date -- reinstalling
warning: linux513-nvidia-470.63.01-5 is up to date -- reinstalling
warning: linux513-virtualbox-host-modules-6.1.26-8 is up to date -- reinstalling
resolving dependencies...
looking for conflicting packages...
Packages (3) linux513-5.13.13-1 linux513-nvidia-470.63.01-5 linux513-virtualbox-host-modules-6.1.26-8
Total Installed Size: 140.92 MiB
Net Upgrade Size: 0.00 MiB
:: Proceed with installation? [Y/n] y
(3/3) checking keys in keyring [#######################################] 100%
(3/3) checking package integrity [#######################################] 100%
(3/3) loading package files [#######################################] 100%
(3/3) checking for file conflicts [#######################################] 100%
(3/3) checking available disk space [#######################################] 100%
:: Running pre-transaction hooks...
(1/2) Remove upgraded DKMS modules
==> Unable to remove module vboxhost/6.1.26_OSE for kernel 5.13.13-1-MANJARO: Not found in dkms status output.
==> Unable to remove module v4l2loopback/0.12.5 for kernel 5.13.13-1-MANJARO: Not found in dkms status output.
(2/2) Save Linux kernel modules
:: Processing package changes...
(1/3) reinstalling linux513 [#######################################] 100%
(2/3) reinstalling linux513-nvidia [#######################################] 100%
(3/3) reinstalling linux513-virtualbox-host-modules [#######################################] 100%
In order to use the new version, reload all virtualbox modules manually.
:: Running post-transaction hooks...
(1/8) Arming ConditionNeedsUpdate...
(2/8) Updating module dependencies...
(3/8) Install DKMS modules
==> Unable to install module vboxhost/6.1.26_OSE for kernel 5.13.13-1-MANJARO: Missing kernel headers.
==> Unable to install module v4l2loopback/0.12.5 for kernel 5.13.13-1-MANJARO: Missing kernel headers.
(4/8) Updating linux initcpios...
==> Building image from preset: /etc/mkinitcpio.d/linux513.preset: 'default'
-> -k /boot/vmlinuz-5.13-x86_64 -c /etc/mkinitcpio.conf -g /boot/initramfs-5.13-x86_64.img
==> Starting build: 5.13.13-1-MANJARO
-> Running build hook: [base]
-> Running build hook: [udev]
-> Running build hook: [autodetect]
-> Running build hook: [modconf]
-> Running build hook: [block]
-> Running build hook: [keyboard]
-> Running build hook: [keymap]
-> Running build hook: [resume]
-> Running build hook: [filesystems]
==> Generating module dependencies
==> Creating gzip-compressed initcpio image: /boot/initramfs-5.13-x86_64.img
==> Image generation successful
==> Building image from preset: /etc/mkinitcpio.d/linux513.preset: 'fallback'
-> -k /boot/vmlinuz-5.13-x86_64 -c /etc/mkinitcpio.conf -g /boot/initramfs-5.13-x86_64-fallback.img -S autodetect
==> Starting build: 5.13.13-1-MANJARO
-> Running build hook: [base]
-> Running build hook: [udev]
-> Running build hook: [modconf]
-> Running build hook: [block]
-> Running build hook: [keyboard]
-> Running build hook: [keymap]
-> Running build hook: [resume]
-> Running build hook: [filesystems]
==> Generating module dependencies
==> Creating gzip-compressed initcpio image: /boot/initramfs-5.13-x86_64-fallback.img
==> Image generation successful
(5/8) Updating Kernel initcpios for Nvidia-DRM...
(6/8) Updating Grub-Bootmenu
Generating grub configuration file ...
Found theme: /usr/share/grub/themes/manjaro/theme.txt
Found linux image: /boot/vmlinuz-5.13-x86_64
Found initrd image: /boot/amd-ucode.img /boot/initramfs-5.13-x86_64.img
Found initrd fallback image: /boot/initramfs-5.13-x86_64-fallback.img
Found linux image: /boot/vmlinuz-5.10-x86_64
Found initrd image: /boot/amd-ucode.img /boot/initramfs-5.10-x86_64.img
Found initrd fallback image: /boot/initramfs-5.10-x86_64-fallback.img
Found linux image: /boot/vmlinuz-5.10-rt-x86_64
Found initrd image: /boot/amd-ucode.img /boot/initramfs-5.10-rt-x86_64.img
Found initrd fallback image: /boot/initramfs-5.10-rt-x86_64-fallback.img
Warning: os-prober will be executed to detect other bootable partitions.
Its output will be used to detect bootable binaries on them and create new boot entries.
Found Windows Boot Manager on /dev/nvme0n1p2@/efi/Microsoft/Boot/bootmgfw.efi
Found Manjaro Linux (21.1.0) on /dev/nvme0n1p5
Adding boot menu entry for UEFI Firmware Settings ...
Found memtest86+ image: /boot/memtest86+/memtest.bin
/usr/bin/grub-probe: warning: unknown device type nvme1n1.
done
(7/8) Restore Linux kernel modules
==> Warning:
-> Kernel has been updated. Modules of the current kernel
-> have been backed up so you can continue to use your
-> computer. However, the new kernel will only work
-> at next boot.
(8/8) Keep rEFInd default kernel