If you extract cboot2_wadmanager_1.5_mod.zip to a formated sd-card, does wadmanager load? If it does, install 3.1u, ios30, elua, and region select with ios36.
If wadmanager does not load, try to format your card with this tool. Then try the formater again. Delete any wads that fail, if it completes, try wadmanager again.
If it continues to fail, try 3.1e-formater.zip, same as before, delete any wads that fail- if it PASS we will change the region back to U.