I believe you want to install 7-mode image on both system.
If yes, then on the node which is picking the clustered ontap image change the below boot argument:
- halt the controller
- at the boot loader, set the environment variable "bootarg.init.boot_clustered" to false
LOADER> setenv bootarg.init.boot_clustered false
LOADER> saveenv
LOADER> bye
Restart the process from beginning.