1.Q:Why do you compile your own openwrt?
A:Because I can. :p Actually it's because the official version doesn't support memory over 900MB , either support more than 1 cpu core. And my machine comes with dual core and 4g memory , so I have to do that to use up all resource.
2.Q:Are you using it just as a router?
A:Of course not , I also use it as a vpn server and samba server. And I love the feature to share files with all devices without powering on my PC.
3.Q:Why there are sda version and sdb version?
A:Depends on your hareware , you might find out your system is installed at the second bios HD (which is sdb) , but for most of cases , you should use sda version.
4.Q:How do I know whether I should use sda version or sdb version?
A:Try sda version first , and if your boot screen stucks at this line "waiting for root at sda2...." , then you should try sdb version.
5.Q:Why can't I install some packages from offical repositories?
A:Because many packages are kernel dependency , and my kernel is different from the official one , so you should install packages I compiled.
6:Q:How to install your packages?
A:Please refer to this wiki=>http://wiki.openwrt.org/doc/techref/opkg#local.repositories