Cannot get a functional dual boot menu

[alreve]

I installed Lubuntu on the SSD of my hp, which also has a 1 To hard disk. I also have windows 10 on that SSD. Before, I tried to install Lubuntu
on the hard disk. 2 versions, both failed to install but Boot Repair can see them. I can delete them if it helps.

After the succesful install on the SSD, when I rebooted, the hp booted straight into windows. Boot repair didn't help (I ran it with the default settings).

I made sure secure boot and fast boot were disabled.

I could boot into Lubuntu Noble Numbat, but to do this I had to repeatedly hit F9 at startup. Then I saw the menu :
"OS Boot Manager (UEFI) - Windows Boot Manager (SanDisk SD9 SN8W-128G-1006)"
"OS Boot Manager (UEFI) - ubuntu (SanDisk SD9 SN8W-128G-1006)".
and I could select Lubuntu with the arrow key.

After quite a lot of fiddling, I discovered /boot/efi/EFI/Microsoft/Boot/bootmgfw.efi
From Lubuntu, I renamed it rem_bootmgfw.efi

Now I see grub menu at startup, with the windows option, but the windows option doesn't function. It says it can't find bootmgfw.efi.

So, basically, I have the choice between a functional menu I can only reach by hitting F9 repeatedly or my current setting where
windows won't boot unless I change back the name of rem_bootmgfw.efi into bootmgfw.efi.

How can I get a proper boot menu, such as grub, to take control at startup, please?

============ Below is the output of Boot Repair ============

Note : The OS#2 (linux): Ubuntu 22.04.5 LTS on sda1 and the OS#3 (linux): Ubuntu 24.04.1 LTS on sda2 are the failed lubuntu installations.

Default settings: __________________________________________________ ____________

The default repair of the Boot-Repair utility would reinstall the grub-efi of
sdb5,
using the following options: sdb1/boot/efi
Additional repair would be performed: unhide-bootmenu-10s use-standard-efi-file

Final advice in case of suggested repair: ______________________________________

Please do not forget to make your UEFI firmware boot on the The OS now in use - Ubuntu 24.04.1 LTS entry (sdb1/efi/****/grub****.efi (**** will be updated in the final message) file) !
If your computer reboots directly into Windows, try to change the boot order in your UEFI firmware.
If your UEFI firmware does not allow to change the boot order, change the default boot entry of the Windows bootloader.
For example you can boot into Windows, then type the following command in an admin command prompt:
bcdedit /set {bootmgr} path \EFI\****\grub****.efi (**** will be updated in the final message)

Note : I've done that, except changing the boot order in my UEFI firmware. Didn't find how to do that.

User settings: __________________________________________________ _______________

modprobe: FATAL: Module efivars not found in directory /lib/modules/6.8.0-47-generic
The settings chosen by the user will reinstall the grub-efi of
sdb5,
using the following options: sdb1/boot/efi
Additional repair will be performed: unhide-bootmenu-10s use-standard-efi-file


/boot/efi added in sdb5/fstab
/dev/sdb5/boot/efi not empty

Unhide GRUB boot menu in sdb5/etc/default/grub

===================== Reinstall the grub-efi of /dev/sdb5 ======================

grub-install --version
grub-install (GRUB) 2.12-1ubuntu7
modprobe: FATAL: Module efivars not found in directory /lib/modules/6.8.0-47-generic
modprobe efivars

efibootmgr -v (filtered) before grub install
BootCurrent: 0005
Timeout: 20 seconds
BootOrder: 0000,3000,0005,2001,2002,2004,0003,0002
Boot0000* Windows Boot Manager HD(1,GPT,1695ed28-bfe9-4fc4-b2c2-bb0e33413587,0x800,0x32000)/File(EFIMicrosoftBootbootmgfw.efi)RC
Boot0001* Windows Boot Manager HD(1,GPT,1695ed28-bfe9-4fc4-b2c2-bb0e33413587,0x800,0x32000)/File(EFIubuntugrubx64.efi)57494e444f57530001000000 88000000780000004200430044004f0042004a004500430054 003d007b00390064006500610038003600320063002d003500 6300640064002d0034006500370030002d0061006300630031 002d0066003300320062003300340034006400340037003900 35007d00000061000100000010000000040000007fff0400
Boot0002* Internal Hard Drive - ST1000LM035-1RK172 BBS(HD,Internal Hard Drive - ST1000LM035-1RK172,0x500)feff05000000000000000000000001062d005 2e602000005190052e6410052e600000002000000000000000 0000000000000000000000000000000000000000000d887c9a e110002010c00d041030a00000000010106000208010106000 00003120a000000000000007fff0400
Boot0003* Internal Hard Drive - SanDisk SD9SN8W-128G-1006 BBS(HD,Internal Hard Drive - SanDisk SD9SN8W-128G-1006,0x500)feff05000000000000000000000001062d0059e 602000005190059e6410059e60000001200000000000000000 00000000000000000000000000000000000000000088ec9ae1 20002010c00d041030a0000000001010600020801010600000 003120a000100000000007fff0400
Boot0005* ubuntu HD(1,GPT,1695ed28-bfe9-4fc4-b2c2-bb0e33413587,0x800,0x32000)/File(EFIubuntushimx64.efi)
Boot2001* EFI USB Device RC
Boot3000* Internal Hard Disk or Solid State Disk RC

uname -r
6.8.0-47-generic

grub-install --efi-directory=/boot/efi --target=x86_64-efi
Installing for x86_64-efi platform.
Installation finished. No error reported.
df /dev/sdb1
mv /boot/efi/EFI/Boot/bootx64.efi /boot/efi/EFI/Boot/bkpbootx64.efi
cp /boot/efi/efi/ubuntu/grubx64.efi /boot/efi/EFI/Boot/bootx64.efi

grub-install --efi-directory=/boot/efi --target=x86_64-efi
Installing for x86_64-efi platform.
Installation finished. No error reported.

efibootmgr -v (filtered) after grub install
BootCurrent: 0005
Timeout: 20 seconds
BootOrder: 0005,0000,3000,2001,2002,2004,0003,0002
Boot0000* Windows Boot Manager HD(1,GPT,1695ed28-bfe9-4fc4-b2c2-bb0e33413587,0x800,0x32000)/File(EFIMicrosoftBootbootmgfw.efi)RC
Boot0001* Windows Boot Manager HD(1,GPT,1695ed28-bfe9-4fc4-b2c2-bb0e33413587,0x800,0x32000)/File(EFIubuntugrubx64.efi)57494e444f57530001000000 88000000780000004200430044004f0042004a004500430054 003d007b00390064006500610038003600320063002d003500 6300640064002d0034006500370030002d0061006300630031 002d0066003300320062003300340034006400340037003900 35007d00000061000100000010000000040000007fff0400
Boot0002* Internal Hard Drive - ST1000LM035-1RK172 BBS(HD,Internal Hard Drive - ST1000LM035-1RK172,0x500)feff05000000000000000000000001062d005 2e602000005190052e6410052e600000002000000000000000 0000000000000000000000000000000000000000000d887c9a e110002010c00d041030a00000000010106000208010106000 00003120a000000000000007fff0400
Boot0003* Internal Hard Drive - SanDisk SD9SN8W-128G-1006 BBS(HD,Internal Hard Drive - SanDisk SD9SN8W-128G-1006,0x500)feff05000000000000000000000001062d0059e 602000005190059e6410059e60000001200000000000000000 00000000000000000000000000000000000000000088ec9ae1 20002010c00d041030a0000000001010600020801010600000 003120a000100000000007fff0400
Boot0005* Ubuntu HD(1,GPT,1695ed28-bfe9-4fc4-b2c2-bb0e33413587,0x800,0x32000)/File(EFIubuntushimx64.efi)
Boot2001* EFI USB Device RC
Boot3000* Internal Hard Disk or Solid State Disk RC

update-grub
Sourcing file `/etc/default/grub'
Sourcing file `/etc/default/grub.d/lubuntu-grub-theme.cfg'
Found theme: /usr/share/grub/themes/lubuntu-grub-theme/theme.txt
Found linux image: /boot/vmlinuz-6.8.0-47-generic
Found initrd image: /boot/initrd.img-6.8.0-47-generic
Found linux image: /boot/vmlinuz-6.8.0-40-generic
Found initrd image: /boot/initrd.img-6.8.0-40-generic
Found memtest86+ 64bit EFI image: /boot/memtest86+x64.efi
Found Ubuntu 22.04.5 LTS (22.04) on /dev/sda1
Found Ubuntu 24.04.1 LTS (24.04) on /dev/sda2
Found Windows Boot Manager on /dev/sdb1@/EFI/Microsoft/Boot/bootmgfw.efi
Adding boot menu entry for UEFI Firmware Settings ...

Unhide GRUB boot menu in sdb5/boot/grub/grub.cfg

Boot successfully repaired.

You can now reboot your computer.
Please do not forget to make your UEFI firmware boot on the The OS now in use - Ubuntu 24.04.1 LTS entry (sdb1/efi/ubuntu/grubx64.efi file) !
If your computer reboots directly into Windows, try to change the boot order in your UEFI firmware.
If your UEFI firmware does not allow to change the boot order, change the default boot entry of the Windows bootloader.
For example you can boot into Windows, then type the following command in an admin command prompt:
bcdedit /set {bootmgr} path \EFI\ubuntu\grubx64.efi


============================ Boot Info After Repair ============================

=> No boot loader is installed in the MBR of /dev/sda.
=> No boot loader is installed in the MBR of /dev/sdb.

sda1: __________________________________________________ ________________________

File system: ext4
Boot sector type: -
Boot sector info:
Operating System: Ubuntu 22.04.5 LTS
Boot files: /etc/fstab /etc/default/grub

sda2: __________________________________________________ ________________________

File system: ext4
Boot sector type: -
Boot sector info:
Operating System: Ubuntu 24.04.1 LTS
Boot files: /etc/fstab /etc/default/grub

sdb1: __________________________________________________ ________________________

File system: vfat
Boot sector type: FAT32
Boot sector info: No errors found in the Boot Parameter Block.
Operating System:
Boot files: /efi/Boot/bkpbootx64.efi /efi/Boot/bootx64.efi
/efi/Boot/fbx64.efi /efi/Boot/mmx64.efi
/efi/ubuntu/grubx64.efi /efi/ubuntu/mmx64.efi
/efi/ubuntu/shimx64.efi /efi/ubuntu/grub.cfg
/efi/Microsoft/Boot/bootmgfw.efi
/efi/Microsoft/Boot/bootmgr.efi
/efi/Microsoft/Boot/SecureBootRecovery.efi

sdb2: __________________________________________________ ________________________

File system:
Boot sector type: -
Boot sector info:

sdb3: __________________________________________________ ________________________

File system: ntfs
Boot sector type: NTFS
Boot sector info: No errors found in the Boot Parameter Block.
Operating System: Windows 10 or 11
Boot files: /Windows/System32/winload.exe

sdb4: __________________________________________________ ________________________

File system: ntfs
Boot sector type: NTFS
Boot sector info: No errors found in the Boot Parameter Block.
Operating System:
Boot files:

sdb5: __________________________________________________ ________________________

File system: ext4
Boot sector type: -
Boot sector info:
Operating System: Ubuntu 24.04.1 LTS
Boot files: /boot/grub/grub.cfg /etc/fstab /etc/default/grub


================================ 4 OS detected =================================

OS#1 (linux): The OS now in use - Ubuntu 24.04.1 LTS on sdb5
OS#2 (linux): Ubuntu 22.04.5 LTS on sda1
OS#3 (linux): Ubuntu 24.04.1 LTS on sda2
OS#4 (windows): Windows 10 or 11 on sdb3

================================ Host/Hardware =================================

CPU architecture: 64-bit
Video: Picasso/Raven 2 [Radeon Vega Series / Radeon Vega Mobile Series] from Advanced Micro Devices, Inc. [AMD/ATI]
BOOT_IMAGE of the installed session in use:
/boot/vmlinuz-6.8.0-47-generic root=UUID=e473ae63-8a11-4c2d-bd34-b23b26bc9c0a ro quiet splash vt.handoff=7
df -Th / : /dev/sdb5 ext4 59G 8.7G 47G 16% /

===================================== UEFI =====================================

BIOS/UEFI firmware: F.13(15.13) from Insyde
The firmware is EFI-compatible, and is set in EFI-mode for this installed-session.
SecureBoot disabled (confirmed by mokutil).
BootCurrent: 0005
Timeout: 20 seconds
BootOrder: 0005,0000,3000,2001,2002,2004,0003,0002
Boot0000* Windows Boot Manager HD(1,GPT,1695ed28-bfe9-4fc4-b2c2-bb0e33413587,0x800,0x32000)/File(\EFI\Microsoft\Boot\bootmgfw.efi)RC
Boot0001* Windows Boot Manager HD(1,GPT,1695ed28-bfe9-4fc4-b2c2-bb0e33413587,0x800,0x32000)/File(\EFI\ubuntu\grubx64.efi)57494e444f57530001000 00088000000780000004200430044004f0042004a004500430 054003d007b00390064006500610038003600320063002d003 5006300640064002d0034006500370030002d0061006300630 031002d0066003300320062003300340034006400340037003 90035007d00000061000100000010000000040000007fff040 0
Boot0002* Internal Hard Drive - ST1000LM035-1RK172 BBS(HD,Internal Hard Drive - ST1000LM035-1RK172,0x500)feff05000000000000000000000001062d005 2e602000005190052e6410052e600000002000000000000000 0000000000000000000000000000000000000000000d887c9a e110002010c00d041030a00000000010106000208010106000 00003120a000000000000007fff0400
Boot0003* Internal Hard Drive - SanDisk SD9SN8W-128G-1006 BBS(HD,Internal Hard Drive - SanDisk SD9SN8W-128G-1006,0x500)feff05000000000000000000000001062d0059e 602000005190059e6410059e60000001200000000000000000 00000000000000000000000000000000000000000088ec9ae1 20002010c00d041030a0000000001010600020801010600000 003120a000100000000007fff0400
Boot0005* Ubuntu HD(1,GPT,1695ed28-bfe9-4fc4-b2c2-bb0e33413587,0x800,0x32000)/File(\EFI\ubuntu\shimx64.efi)
Boot2001* EFI USB Device RC
Boot3000* Internal Hard Disk or Solid State Disk RC


============================= Drive/Partition Info =============================

Disks info: __________________________________________________ __________________

sdb : is-GPT, no-BIOSboot, has---ESP, not-usb, not-mmc, has-os, has-win, 2048 sectors * 512 bytes
sda : is-GPT, no-BIOSboot, has-noESP, not-usb, not-mmc, has-os, no-wind, 2048 sectors * 512 bytes

Partitions info (1/3): __________________________________________________ _______

sdb5 : is-os, 64, apt-get, signed grub-pc grub-efi , grub2, grub-install, grubenv-ok, update-grub, end-after-100GB
sdb4 : no-os, 64, nopakmgr, no-docgrub, nogrub, nogrubinstall, no-grubenv, noupdategrub, end-after-100GB
sdb3 : is-os, 64, nopakmgr, no-docgrub, nogrub, nogrubinstall, no-grubenv, noupdategrub, not-far
sdb1 : no-os, 64, nopakmgr, no-docgrub, nogrub, nogrubinstall, no-grubenv, noupdategrub, not-far
sda2 : is-os, 64, apt-get, signed grub-pc grub-efi , grub2, grub-install, no-grubenv, update-grub, end-after-100GB
sda1 : is-os, 64, apt-get, signed grub-pc grub-efi , grub2, grub-install, no-grubenv, update-grub, end-after-100GB

Partitions info (2/3): __________________________________________________ _______

sdb5 : isnotESP, fstab-has-goodEFI, no-nt, no-winload, no-recov-nor-hid, no-bmgr, notwinboot, ext4
sdb4 : isnotESP, part-has-no-fstab, no-nt, no-winload, recovery-or-hidden, no-bmgr, notwinboot, ntfs
sdb3 : isnotESP, part-has-no-fstab, no-nt, haswinload, no-recov-nor-hid, no-bmgr, notwinboot, ntfs
sdb1 : is---ESP, part-has-no-fstab, no-nt, no-winload, no-recov-nor-hid, no-bmgr, notwinboot, vfat
sda2 : isnotESP, fstab-without-efi, no-nt, no-winload, no-recov-nor-hid, no-bmgr, notwinboot, ext4
sda1 : isnotESP, fstab-has-goodEFI, no-nt, no-winload, no-recov-nor-hid, no-bmgr, notwinboot, ext4

Partitions info (3/3): __________________________________________________ _______

sdb5 : not--sepboot, with-boot, fstab-without-boot, not-sep-usr, with--usr, fstab-without-usr, std-grub.d, sdb
sdb4 : not--sepboot, no---boot, part-has-no-fstab, not-sep-usr, no---usr, part-has-no-fstab, no--grub.d, sdb
sdb3 : not--sepboot, no---boot, part-has-no-fstab, not-sep-usr, no---usr, part-has-no-fstab, no--grub.d, sdb
sdb1 : not--sepboot, no---boot, part-has-no-fstab, not-sep-usr, no---usr, part-has-no-fstab, no--grub.d, sdb
sda2 : not--sepboot, with-boot, fstab-without-boot, not-sep-usr, with--usr, fstab-without-usr, std-grub.d, sda
sda1 : not--sepboot, with-boot, fstab-without-boot, not-sep-usr, with--usr, fstab-without-usr, std-grub.d, sda

fdisk -l (filtered): __________________________________________________ _________

Disk sda: 931.51 GiB, 1000204886016 bytes, 1953525168 sectors
Disk identifier: E2203556-7D3B-43BA-827A-A667A7BEDB87
Start End Sectors Size Type
sda1 977069282 1953520064 976450783 465.6G Linux filesystem
sda2 618496 977069280 976450785 465.6G EFI System
Partition table entries are not in disk order.
Disk sdb: 119.24 GiB, 128035676160 bytes, 250069680 sectors
Disk identifier: 9EDAE009-C871-4072-88DA-061A32150D06
Start End Sectors Size Type
sdb1 2048 206847 204800 100M EFI System
sdb2 206848 239615 32768 16M Microsoft reserved
sdb3 239616 124617393 124377778 59.3G Microsoft basic data
sdb4 248995840 250066943 1071104 523M Windows recovery environment
sdb5 124617395 248995169 124377775 59.3G Linux filesystem
Partition table entries are not in disk order.

parted -lm (filtered): __________________________________________________ _______

sda:1000GB:scsi:512:4096:gpt:ATA ST1000LM035-1RK1:;
2:317MB:500GB:500GB:ext4:lubuntu_2404:boot, esp;
1:500GB:1000GB:500GB:ext4:root:;
sdb:128GB:scsi:512:4096:gpt:ATA SanDisk SD9SN8W-:;
1:1049kB:106MB:105MB:fat32:EFI system partition:boot, esp, no_automount;
2:106MB:123MB:16.8MB::Microsoft reserved partition:msftres, no_automount;
3:123MB:63.8GB:63.7GB:ntfs:Basic data partition:msftdata;
5:63.8GB:127GB:63.7GB:ext4:root:;
4:127GB:128GB:548MB:ntfs::hidden, diag, no_automount;

Free space >10MiB: __________________________________________________ ____________

sda: 0.02MiB:302MiB:302MiB

blkid (filtered): __________________________________________________ ____________

NAME FSTYPE UUID PARTUUID LABEL PARTLABEL
sda
├─sda1 ext4 940bd12b-0dc1-46ed-87fe-bfdb0eb9715a 0743ba8e-41a2-2348-a1b6-bd267db8e265 root
└─sda2 ext4 2004cf58-df38-4ee0-9743-de134566f377 0a31c475-0ebc-43de-ae7e-da3195c5c047 lubuntu_2404
sdb
├─sdb1 vfat 98FB-4A13 1695ed28-bfe9-4fc4-b2c2-bb0e33413587 EFI system partition
├─sdb2 c060020c-f85c-4909-9707-34ddafa37d15 Microsoft reserved partition
├─sdb3 ntfs E4DC0031DC000092 e349bdfd-ec73-4acd-b521-94648fac4d18 SSD Basic data partition
├─sdb4 ntfs 3CF02F0CF02ECC48 d339b6c4-239c-4c12-9299-291012434792
└─sdb5 ext4 e473ae63-8a11-4c2d-bd34-b23b26bc9c0a c4d15a4d-60f5-b043-b259-8d25ca8ef7a1 root

Mount points (filtered): __________________________________________________ _____

Avail Use% Mounted on
/dev/sda1 427G 2% /mnt/boot-sav/sda1
/dev/sda2 425.9G 2% /mnt/boot-sav/sda2
/dev/sdb3 21.1G 64% /mnt/boot-sav/sdb3
/dev/sdb4 88.7M 83% /mnt/boot-sav/sdb4
/dev/sdb5 46.5G 15% /
efivarfs 81.8K 46% /sys/firmware/efi/efivars

Mount options (filtered): __________________________________________________ ____

/dev/sda1 ext4 rw,relatime
/dev/sda2 ext4 rw,relatime
/dev/sdb3 fuseblk rw,relatime,user_id=0,group_id=0,allow_other,blksi ze=4096
/dev/sdb4 fuseblk rw,relatime,user_id=0,group_id=0,allow_other,blksi ze=4096
/dev/sdb5 ext4 rw,relatime,discard

========================== sda1/etc/fstab (filtered) ===========================

# <file system> <mount point> <type> <options> <dump> <pass>
UUID=2004cf58-df38-4ee0-9743-de134566f377 /boot/efi ext4 umask=0077 0 2
UUID=940bd12b-0dc1-46ed-87fe-bfdb0eb9715a / ext4 defaults 0 1
/swapfile swap swap defaults 0 0

======================= sda1/etc/default/grub (filtered) =======================

GRUB_DEFAULT=0
GRUB_TIMEOUT_STYLE=hidden
GRUB_TIMEOUT=0
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX=""

==================== sda1: Location of files loaded by Grub ====================

GiB - GB File Fragment(s)
469.502778053 = 504.124769280 boot/vmlinuz 1
469.502778053 = 504.124769280 boot/vmlinuz-6.8.0-40-generic 1
469.502778053 = 504.124769280 boot/vmlinuz.old 1
470.352887154 = 505.037566976 boot/initrd.img 1
470.352887154 = 505.037566976 boot/initrd.img-6.8.0-40-generic 1
470.352887154 = 505.037566976 boot/initrd.img.old 1

===================== sda1: ls -l /etc/grub.d/ (filtered) ======================

-rwxr-xr-x 1 root root 18683 Dec 18 2022 10_linux
-rwxr-xr-x 1 root root 43031 Dec 18 2022 10_linux_zfs
-rwxr-xr-x 1 root root 14387 Dec 18 2022 20_linux_xen
-rwxr-xr-x 1 root root 13369 Dec 18 2022 30_os-prober
-rwxr-xr-x 1 root root 1372 Dec 18 2022 30_uefi-firmware
-rwxr-xr-x 1 root root 700 May 17 2023 35_fwupd
-rwxr-xr-x 1 root root 214 Dec 18 2022 40_custom
-rwxr-xr-x 1 root root 215 Dec 18 2022 41_custom

========================== sda2/etc/fstab (filtered) ===========================

# <file system> <mount point> <type> <options> <dump> <pass>
UUID=2004cf58-df38-4ee0-9743-de134566f377 / ext4 defaults 0 1
/swapfile swap swap defaults 0 0

======================= sda2/etc/default/grub (filtered) =======================

GRUB_DEFAULT=0
GRUB_TIMEOUT_STYLE=hidden
GRUB_TIMEOUT=0
GRUB_DISTRIBUTOR=`( . /etc/os-release; echo ${NAME:-Ubuntu} ) 2>/dev/null || echo Ubuntu`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX=""

==================== sda2: Location of files loaded by Grub ====================

GiB - GB File Fragment(s)
4.411827087 = 4.737163264 boot/vmlinuz 1
3.941654205 = 4.232318976 boot/vmlinuz-6.8.0-41-generic 1
4.411827087 = 4.737163264 boot/vmlinuz-6.8.0-47-generic 1
3.941654205 = 4.232318976 boot/vmlinuz.old 1
5.718132019 = 6.139797504 boot/initrd.img 2
4.046760559 = 4.345176064 boot/initrd.img-6.8.0-41-generic 1
5.718132019 = 6.139797504 boot/initrd.img-6.8.0-47-generic 2
4.046760559 = 4.345176064 boot/initrd.img.old 1

===================== sda2: ls -l /etc/grub.d/ (filtered) ======================

-rwxr-xr-x 1 root root 18133 Apr 4 2024 10_linux
-rwxr-xr-x 1 root root 43202 Apr 4 2024 10_linux_zfs
-rwxr-xr-x 1 root root 14513 Apr 4 2024 20_linux_xen
-rwxr-xr-x 1 root root 786 Apr 4 2024 25_bli
-rwxr-xr-x 1 root root 13120 Apr 4 2024 30_os-prober
-rwxr-xr-x 1 root root 1174 Apr 4 2024 30_uefi-firmware
-rwxr-xr-x 1 root root 722 Apr 5 2024 35_fwupd
-rwxr-xr-x 1 root root 214 Apr 4 2024 40_custom
-rwxr-xr-x 1 root root 215 Apr 4 2024 41_custom

===================== sdb1/efi/ubuntu/grub.cfg (filtered) ======================

search.fs_uuid e473ae63-8a11-4c2d-bd34-b23b26bc9c0a root hd1,gpt5
set prefix=($root)'/boot/grub'
configfile $prefix/grub.cfg

====================== sdb5/boot/grub/grub.cfg (filtered) ======================

Ubuntu e473ae63-8a11-4c2d-bd34-b23b26bc9c0a
Ubuntu 22.04.5 LTS (22.04) (on sda1) 940bd12b-0dc1-46ed-87fe-bfdb0eb9715a
Ubuntu 24.04.1 LTS (24.04) (on sda2) 2004cf58-df38-4ee0-9743-de134566f377
Windows Boot Manager (on sdb1) osprober-efi-98FB-4A13
### END /etc/grub.d/30_os-prober ###
UEFI Firmware Settings uefi-firmware
### END /etc/grub.d/30_uefi-firmware ###

========================== sdb5/etc/fstab (filtered) ===========================

# <file system> <mount point> <type> <options> <dump> <pass>
UUID=e473ae63-8a11-4c2d-bd34-b23b26bc9c0a / ext4 defaults,discard 0 1
/swapfile swap swap defaults 0 0
tmpfs /tmp tmpfs defaults,noatime,mode=1777 0 0
UUID=98FB-4A13 /boot/efi vfat defaults 0 1

======================= sdb5/etc/default/grub (filtered) =======================

GRUB_DEFAULT=0
GRUB_TIMEOUT_STYLE=menu
GRUB_TIMEOUT=10
GRUB_DISTRIBUTOR=`( . /etc/os-release; echo ${NAME:-Ubuntu} ) 2>/dev/null || echo Ubuntu`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX=""
GRUB_DISABLE_OS_PROBER=false

==================== sdb5: Location of files loaded by Grub ====================

GiB - GB File Fragment(s)
75.301396847 = 80.854259200 boot/grub/grub.cfg 1
62.162694454 = 66.746684928 boot/vmlinuz 1
65.865808010 = 70.722872832 boot/vmlinuz-6.8.0-40-generic 2
62.162694454 = 66.746684928 boot/vmlinuz-6.8.0-47-generic 1
65.865808010 = 70.722872832 boot/vmlinuz.old 2
76.000993252 = 81.605445120 boot/initrd.img 1
76.071313381 = 81.680950784 boot/initrd.img-6.8.0-40-generic 2
76.000993252 = 81.605445120 boot/initrd.img-6.8.0-47-generic 1
76.071313381 = 81.680950784 boot/initrd.img.old 2

===================== sdb5: ls -l /etc/grub.d/ (filtered) ======================

-rwxr-xr-x 1 root root 18133 Apr 4 2024 10_linux
-rwxr-xr-x 1 root root 43202 Apr 4 2024 10_linux_zfs
-rwxr-xr-x 1 root root 14513 Apr 4 2024 20_linux_xen
-rwxr-xr-x 1 root root 786 Apr 4 2024 25_bli
-rwxr-xr-x 1 root root 13120 Apr 4 2024 30_os-prober
-rwxr-xr-x 1 root root 1174 Apr 4 2024 30_uefi-firmware
-rwxr-xr-x 1 root root 722 Aug 21 20:39 35_fwupd
-rwxr-xr-x 1 root root 214 Dec 18 2022 40_custom
-rwxr-xr-x 1 root root 215 Dec 18 2022 41_custom

[tea for one]

After quite a lot of fiddling, I discovered /boot/efi/EFI/Microsoft/Boot/bootmgfw.efi
From Lubuntu, I renamed it rem_bootmgfw.efi
Now I see grub menu at startup, with the windows option, but the windows option doesn't function. It says it can't find bootmgfw.efi.
So, basically, I have the choice between a functional menu I can only reach by hitting F9 repeatedly or my current setting where
windows won't boot unless I change back the name of rem_bootmgfw.efi into bootmgfw.efi.

First task is to change it back to the original to allow Windows to boot normally.

How can I get a proper boot menu, such as grub, to take control at startup, please?

Before we go any further, where do you wish Lubuntu 24.04 to be installed?
I imagine it will be on sda because Windows is already on sdb (the smaller 128GB disk)?

[yancek]

Both of your drives are GPT so if you wanted a Legacy install on sda, you would need to create a bios_boot partition on the drive on which to put the core.img file then install Grub code to the MBR of that drive. Boot repair shows you did not do this.

You have an install of Ubuntu on sdb5 with the grub efi files on an EFI partition of that drive. The reason you can't boot windows is because you renamed the windows boot file and you need to change it back to the correct name as mentioned above. After doing that run sudo update-grub to get a new correct menu. Tapping the F9 key is the standard method of accessing one time options on many HP computers

If you want Ubuntu on the other drive, post back so someone can make suggestions.