I had a Lenovo Thinkpad T490 with a 256GB NVMe 2280 SSD loading Windows 11.
I want to install Kubuntu 26.04 on this laptop. For this I got another 256GB NVMe 2230 SSD and connected it to the WLAN port of the laptop.
Windows recognised this drive correctly. Then I boot from Kubuntu Live USB and that recognises both drives as well.
I installed Kubuntu on the new SSD with a partition configuration of 300MB FAT32 partition mounted to /boot/efi and boot flag on, and the rest of the drive formatted to ext4 mounted to /.
Install process goes on smoothly and it says "Finished". However, on reboot (after removing the live USB), it directly boots to Windows without the dual boot options.
So, as suggested in a Youtube video, I removed the original 2280 SSD and then reinstalled Kubuntu on the new 2230 SSD using the live USB (this time used Erase Disk option instead of manual partitioning).
This time again, the install went on smoothly, but when I rebooted after removing the liveusb, it doesn't show boot screen at all. Instead the BIOS asks for a medium to boot from.
I'd like to mention that in case of both installs, Kubuntu shows in the BIOS boot priority list and it didn't work even after putting it on the top of the list.
If I press F12 on boot to bring up the boot menu, Kubuntu is present. But when I press enter on it, the screen just blinks and nothing happens.
I am returning to Linux after 15 years, so please be patient with me.
Output of efibootmgr from live USB is:
kubuntu@kubuntu:~$ efibootmgr
BootCurrent: 001F
Timeout: 2 seconds
BootOrder: 0001,001C,0010,0011,0012,0013,0014,0015,001B,001F,0019,001A,0000,001D,001E,0020,0021,0022,0023
Boot0000* Windows Boot Manager HD(1,GPT,76f26192-bf42-41dc-b9e9-43d8205dd33d,0x800,0x32000)/\EFI\ubuntu\grubx64.efi57494e444f5753000100000088000000780000004200430044004f0042004a004500430054003d007b00390064006500610038003600320063002d0035006300640064002d0034006500370030002d0061006300630031002d006600330032006200330034003400640034003700390035007d00000033000100000010000000040000007fff0400
Boot0001* Kubuntu HD(1,GPT,96c89b38-a577-4bde-a1c4-8ded1adb3746,0x1000,0x96000)/\EFI\ubuntu\shimx64.efi
Boot0010 Setup FvFile(721c8b66-426c-4e86-8e99-3457c46ab0b9)
Boot0011 Boot Menu FvFile(126a762d-5758-4fca-8531-201a7f57f850)
Boot0012 Diagnostic Splash Screen FvFile(a7d8d9a6-6ab0-4aeb-ad9d-163e59a7a380)
Boot0013 Lenovo Diagnostics FvFile(3f7e615b-0d45-4f80-88dc-26b234958560)
Boot0014 Regulatory Information FvFile(478c92a0-2622-42b7-a65d-5894169e4d24)
Boot0015 ThinkShield secure wipe FvFile(3593a0d5-bd52-43a0-808e-cbff5ece2477)
Boot0016 Startup Interrupt Menu FvFile(f46ee6f4-4785-43a3-923d-7f786c3c8479)
Boot0017 Rescue and Recovery FvFile(665d3f60-ad3e-4cad-8e26-db46eee9f1b5)
Boot0018 MEBx Hot Key FvFile(ac6fd56a-3d41-4efd-a1b9-870293811a28)
Boot0019* USB CD VenMsg(bc7838d2-0f82-4d60-8316-c068ee79d25b,86701296aa5a7848b66cd49dd3ba6a55)
Boot001A* USB FDD VenMsg(bc7838d2-0f82-4d60-8316-c068ee79d25b,6ff015a28830b543a8b8641009461e49)
Boot001B* NVMe0 VenMsg(bc7838d2-0f82-4d60-8316-c068ee79d25b,001c199932d94c4eae9aa0b6e98eb8a400)
Boot001C* NVMe1 VenMsg(bc7838d2-0f82-4d60-8316-c068ee79d25b,001c199932d94c4eae9aa0b6e98eb8a401)
Boot001D* ATA HDD0 VenMsg(bc7838d2-0f82-4d60-8316-c068ee79d25b,91af625956449f41a7b91f4f892ab0f602)
Boot001E* ATA HDD1 VenMsg(bc7838d2-0f82-4d60-8316-c068ee79d25b,91af625956449f41a7b91f4f892ab0f601)
Boot001F* USB HDD VenMsg(bc7838d2-0f82-4d60-8316-c068ee79d25b,33e821aaaf33bc4789bd419f88c50803)
Boot0020* PXE BOOT VenMsg(bc7838d2-0f82-4d60-8316-c068ee79d25b,78a84aaf2b2afc4ea79cf5cc8f3d3803)
Boot0021* LENOVO CLOUD VenMsg(bc7838d2-0f82-4d60-8316-c068ee79d25b,ad38ccbbf7edf04d959cf42aa74d3650)/Uri(https://download.lenovo.com/pccbbs/cdeploy/efi/boot.efi)
Boot0022 Other CD VenMsg(bc7838d2-0f82-4d60-8316-c068ee79d25b,aea2090adfde214e8b3a5e471856a35406)
Boot0023 Other HDD VenMsg(bc7838d2-0f82-4d60-8316-c068ee79d25b,91af625956449f41a7b91f4f892ab0f606)
Boot0024* IDER BOOT CDROM PciRoot(0x0)/Pci(0x14,0x0)/USB(11,1)
Boot0025* IDER BOOT Floppy PciRoot(0x0)/Pci(0x14,0x0)/USB(11,0)
Boot0026* ATA HDD VenMsg(bc7838d2-0f82-4d60-8316-c068ee79d25b,91af625956449f41a7b91f4f892ab0f6)
Boot0027* ATAPI CD VenMsg(bc7838d2-0f82-4d60-8316-c068ee79d25b,aea2090adfde214e8b3a5e471856a354)
Taking hints from the comments and from google AI mode, I figured that I need to install kubuntu on the new drive, but point to the efi partition on the original drive for mounting /boot/efi.
So this time, my install summary looks like this: Kubuntu install summary
Now, after restart, grub pops up, but still does not show me the boot options. This is the screen after restart: Grub Screen
What next?