The PWR Config commands work perfectly. Is there a way to save them permanently?
Yes. But you will need a USB drive of some sort inserted to trigger the process. (There may be another way, too)
Enable SSH access LAN only.
In a terminal (Putty is great for this) log into your router
You will use the VI editor to create a file and enter contents
vi /jffs/post-mount (Enter)
Enter insert mode by pressing i then Enter
#!/bin/sh
pwr config --wait on
Then type :wq to save and exit VI
Set permissions in the file
chmod 755 /jffs/post-mount
Next enter the NVRAM edit
nvram set script_usbmount="/jffs/post-mount"
nvram commit
That's it. When you insert a USB drive the post-mount script will run. This was originally intended to mount a swap file which may be a good idea if you use Samba.
To make a swap file on a thumb drive
Run these commands to make a 512 MB swap file on the USB drive labeled 32GB (Use the label of your thumb drive)
dd if=/dev/zero of=/tmp/mnt/32GB/myswap.swp bs=1k count=524288
mkswap /tmp/mnt/32GB/myswap.swp
swapon /tmp/mnt/32GB/myswap.swp
Then the post-mount file contents will look like
#!/bin/sh
swapon /tmp/mnt/32GB/myswap.swp
pwr config --cpuwait on