How to install on Buffalo WHR-300HP2

Hello, I'm looking to switch from dd-wrt to Open and have some questions. The device page indicates it is supported - there is an update image but no install image. There's also no specific instructions nor chatter on the forums from what I could find. Can anybody explain whether it's ok to use the update image to come from factory, or why there would be an update image and no image for an initial install? Thank you.

Bump. To keep it productive, I dug through the download directories and observed no factory.bin for this device, but I did notice a handful of mt7620 sysupgrade.bins. I'm quite curious to know if I can find another device that has no factory.bin but DOES have a sysupgrade.bin with custom install procedures, can I template my job off of that safely? Thanks for the assist.

edit: I found a somewhat similar Buffalo device having only a sysupgrade image with install directions. It essentially says to boot a compiled initramfs image, boot it and then install the sysupgrade.bin from there. Is this the tactic needed for my device? If so, where would I look for the initramfs image?

OK, I'm talking to myself some more but hopefully someone comes across and provides guidance. I'm guessing after more research that I'm going to want to use the Image Builder to create an image for my device profile. The user guide did not explain what the output would be, whether the image would be suitable for factory flash or just an upgrade, so I'm still not sure. Any ideas? Thank you.

First, if ddwrt is loaded now, follow ddwrt directions to flash back to stock Buffalo firmware. Any advice you receive here would assume you're starting from stock.

Is the stock firmware OpenWrt based? If so, you would use a sysupgrade directly over the stock.

Thanks. The stock firmware is not Open based, it's DD-WRT based.

Bump - Any news? I have a WHR-300HP2 I'd like to play with, and I'm completely new at this game, so it would be Really Helpful to hear if someone can give me specific installation instructions.