It appears I was correct in my previous post in that I should flash with the factory image first. However, it is listed under WR740N, not TL-WR740N. I then went here and managed to find my router. So, because I'm not using a Broadcom chipset, I'm assuming it should be smooth sailing, is that right? The router I want to install this on is an Atheros AR7240 CPU chip with an Atheros 9285 wireless NIC. It said that I should check the Peacock thread here, This thread says it's for Broadcom SoC only. Now that I sort of know what file I've got to use, I went to the installation wiki These photos might give others an idea of the expected differences between v1.0 and v2.0.

However, they don't specifically list the TP-Link TL-740N. I really like their documentation, it's quite comprehensive. Here are some photos of the different versions of hardware. Since I was having so much trouble with DD-WRT, I decided to look at OpenWRT. I'm going to look at the DD-WRT documentation a bit more. I have version a TP-Link TL-740N v1.8 so I guess I'll just have a to take a small chance to see if it works ok. Thanks pal! I think I need to flash the factory one first, right? It's called factory-to-ddwrt.bin At least that seems to be the sort of thing you need to do on OpenWRT.

Dd wrt v24 sp2 tethering