The output should look something like this example...
$ sudo file /boot/vmlinuz-4.15.0-32-generic
Example output...
/boot/vmlinuz-4.15.0-32-generic: Linux kernel x86 boot executable bzImage, version 4.15.0-32-generic (buildd@lgw01-amd64-039) #35-Ubuntu SMP Fri Aug 10 17:58:07 UTC 2018, RO-rootFS, swap_dev 0x7, Normal VGA
Notice that the format of the version information ("version 4.15.0-32-generic") in this example is of the form:
number.number.number-number
This is the format Cubic is looking for. Since you are compiling your own kernel, your version may have a different format than what Cubic expects.
Ray,
Your issue is different than the issue Brian reported in this bug.
Looking again at your comment #2, I see that the output of...
$ file /home/ubuntu/ image/squashfs- root/boot/ vmlinuz- 4.18.0- rc2-udl+
..is producing a result that Cubic can not parse.
The output should look something like this example...
$ sudo file /boot/vmlinuz- 4.15.0- 32-generic
Example output...
/boot/vmlinuz- 4.15.0- 32-generic: Linux kernel x86 boot executable bzImage, version 4.15.0-32-generic (buildd@ lgw01-amd64- 039) #35-Ubuntu SMP Fri Aug 10 17:58:07 UTC 2018, RO-rootFS, swap_dev 0x7, Normal VGA
Notice that the format of the version information ("version 4.15.0-32-generic") in this example is of the form:
number. number. number- number
This is the format Cubic is looking for. Since you are compiling your own kernel, your version may have a different format than what Cubic expects.
If you can share the output of...
$ file /home/ubuntu/ image/squashfs- root/boot/ vmlinuz- 4.18.0- rc2-udl+
...I ~may~ be able to accommodate a generalization for your scenario in Cubic.