vmlinuz file not found error after selecting a different iso boot kernel

[Cubic PPA]

When booting a custom Live ISO that was created by selecting a different boot kernel in Cubic, the Live ISO will not boot. The error "casper/vmlinuz: file not found" appears on the screen when booting the customized Live ISO.

[Thorsten Wagner (totto)]

I can reproduce the error, but also with the original kernel of bionic beaver (Ubuntu 18.04) I can not get a working iso. Definetely, the outcome in both cases is different, meaning that the boot process fails at different stages (initial boot for custom kernel, after "try ubuntu" for original kernel).

[Cubic PPA (cubic-wizard)]

A side effect of Cubic's capability of selecting an ISO boot kernel resulted in an unbootable ISO, even when the default original ISO kernel is selected.

For release 2018.06-29, temporarily disabled Cubic's ability to change the ISO boot kernel. (Only the default kernel will be listed, even though other kernels may be available).

Thus, the ISO's original kernel will be used by Cubic, and this should eliminate the boot issues.