Triple-Boot: Windows 10, ubuntu 18.04 LTS, Clear Linux OS, each its own SSD

Hi all!

I am struggling to incorporate Clear Linux’s boot script unto grub customizer, that’s to say, I need help in booting into Clear Linux in a system with three SSD’s–(1) Ubuntu 18.04, (2) Windows 10, and (3) Clear Linux. CL was the last addition, whereas each OS is in its own SSD. I am operating grub customizer from within ubuntu.
GRUB has captured the Clear OS attributes or parameters when I ran the boot repair tool yannubuntu.boot-repair Please see excerpt from output. Unfortunately I don’t know the exact Linux/GRUB script to add to grub-customizer. Something’s obviously missing. Though I love CL, it’s super fast as reported continuously hyped in many recent articles.

Let me migrate my issue from another forum and add below:

This may be due motherboard than anything having to do with Linux/Grub or Clear Linux’s systemd. I am trying to run a desktop PC with 3 different OS’s, each in its own SSD hard drive. I do not want to mess with partitions, sharing or things along that route. Even better if I can encapsulate each OS in its own environment, then the better. I’ve had Windows 10 and ubuntu on separate SSD drives for years on, and recently when I tried out and included Clear Linux OS, well, here’s where the difficulty starts. In past I’ve used Grub customizer to fiddle and maneuver and select desired OS at boot and no issues. But with inclusion of Clear Linux OS on the SSD, need help/ideas on how-to.

The motherboard is ASUS PRIME X370-PRO. This is what the bios shows. Notice the Samsung SSD shows up twice with the regular SATA selection and as the UEFI OS. And disabling UEFI is not recommended or advised.

SATA6G_2: ADATA SU800 SSD ------>> Windows 10 OS
SATA6G_3: ASUS DRW-24B1ST j DVD Drive.
SATA6G_5: Patriot Spark SSD ------>> ubuntu 18.04 LTS
SATA6G_7: WDC WD2001FASS-00W2B0 … just a regular HDD for storage
SATA6G_8: Samsung SSD 850 EVO 250GB ------>> Clear Linux OS
UEFI OS (SATA6G_8: Samsung SSD 850 EVO 250 GB)

—I am just trying to have a menu selection at boot that will give me a choice of going to any of the 3 OS.

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

sdc1: __

File system: vfat
Boot sector type: FAT32
Boot sector info: No errors found in the Boot Parameter Block.
Operating System:
Boot files: /efi/org.clearlinux/bootloaderx64.efi
/efi/org.clearlinux/loaderx64.efi

sdc2: __

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

sdc3: __

File system: ext4
Boot sector type: -
Boot sector info:
Operating System: Clear Linux OS
Boot files:

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

=================== os-prober:
/dev/sdb1:The OS now in use - Ubuntu 18.04.3 LTS CurrentSession:linux
/dev/sda1:Windows 10:Windows:chain
/dev/sdc3:Clear Linux OS:Clear:linux

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Thank you very much!!!