I have a Linksys WRT3200ACM with the Express VPN software flashed. I don't want to brick it, so can someone provide step by step instructions? Thanks in advance.
The recommended way to go from another third party firmware to OpenWrt is to follow that third party's directions to flash the router back with stock firmware, then install OpenWrt from the stock firmware.
Since this model is dual partition you should flash stock firmware twice-- after the first flash to stock firmware boots, log in and use it to "upgrade" with the same stock firmware again. This will have the stock written to both partitions to completely remove all old firmware.
Thanks. I will give that a go.