While doing some bigger downloads, my wifi network used to have big problems, seeing tx errors, frame errors on the router. The router is old ASUS WL-500g Deluxe which was running OpenWrt Kamikaze up to now. I was anyway thinking going for something with 802.11a or 802.11n support, so I started to look for replacement. While looking for it and checking what newer boxes are supported by OpenWrt, I noticed, that I can finally try using 2.6 kernel and I should get working wireless as well with free (what was not possible for very long time).
I gave it a try and upgraded to Backfire 10.03.1-rc4. And looks there is no need to upgrade hardware right now. No more tx errors, the wireless is much more stable and faster.
Thanks to anybody who helped to create free drivers for Broadcom 4306 wireless chip.
PS: Upgrading OpenWrt while keeping configuration lead to horrible mess in my case, so I rather did clean install reconfiguring everything and rediscovering all errors I've made in the past.