when you say that the validation image works, are you 100% sure you dont have still bits of it on your SD ? the rootfs and rootwait options were never in any ubuntu image and it is not clear what you are booting.
aside from that, who told you to remove the whole first line from the boot.scr, this will definitely not boot anymore since it is the line that contains the load command for the kernel. at most you can delete the first few (unreadable) chars from that line, but not the complete line.
when you say that the validation image works, are you 100% sure you dont have still bits of it on your SD ? the rootfs and rootwait options were never in any ubuntu image and it is not clear what you are booting.
aside from that, who told you to remove the whole first line from the boot.scr, this will definitely not boot anymore since it is the line that contains the load command for the kernel. at most you can delete the first few (unreadable) chars from that line, but not the complete line.