mine is a proper crimper... must be the plugs
So, good news and bad news
Seeing the case I assumed it was a WRT54G unit but it's a WAP54G. Checking the DDWRT website it can load the custom firmware but only the smallest version because it only has 8mb ram and 2mb flash. The install is tricky and risky and there is good chance of bricking the unit.
The good news is that unit is exactly what you are looking for if you can run a cable to the shed as it's a Wireless Access Point, all you would need to do is factory default it and run through the setup, you could set it all up in the house first as it only needs a cable from the main router.
What you won't have is extra ethernet ports but you can achieve that with a small ethernet hub in the shed and plug the WAP into that.
Here's the support page, it has the user manual and firmware downloads.
https://www.linksys.com/us/support-product?pid=01t80000003KWvqAAG
I've just had a read and that unit doesn't broadcast the SSID by default which is good as in a shed it's likely many more people will see it. All that means is you need manually type the SSID in to your device. Once you've connected once you don't need to do it again. You can enable the broadcast while you are setting it for testing purposes.
It is older tech so won't be as secure as a modern unit but for free it will be ideal for what you need.
i can even connect to the bloody thing is there a default password
i tried thatYou'll need to factory default it, press the reset button for 10 seconds
direct or via the router?Are you connected via ethernet?
The default IP address is 192.168.1.245 and the default password is admin, leave the username blank
Not sure if the admin password will allow you connect directly to Wifi