Original Realtek Openwrt sources: https://sourceforge.net/projects/rtl8197xd-v2-5-pkg/

Now it has fully working USB for rtl8196e! Yes, you can setup extroot, dlna and other useful OpenWRT features right now.

COMPILATION

1. You need to have installed gcc, binutils, bzip2, flex, python, perl, make,
   find, grep, diff, unzip, gawk, getopt, subversion, libz-dev and libc headers.
2. Run "make menuconfig" , change configuration as you want. Save it.
3. Execute "make" (build image) or "make V=99" (build image with compiling log).
4. After error   ynyynyyyyynnynyyyynnyyyynnyynnnyyyy' failed
   change: /staging_dir/host/bin/automake and automake-1.11 line
   ${([^ \t=:+{}]+)}/ to $\{([^ \t=:+{}]+)}/
5. Run "make" or "make V=99" again.

6. To build a single package: "make package/<Your_Package>/compile"

INSTALLING

1.  Change IP address PC to 192.168.1.5 netmask 255.255.255.0
2.  Turn off router.
3.  Hold the reset button and turn the router power, wait about 10 seconds (must
    change the nature of the router blinking LED), and release the reset button.
4.  Open TFTP client.
5.  Set IP 192.168.1.6 and Port 69.
6.  Choose openwrt-realtek-rtl8196e-AP-fw.bin file.
7.  Click "Send" button.
8.  Wait few minutes.
9.  Return IP settings PC to default.
10. Visit http://192.168.1.1, set a password on the root and connect through SSH
    (eg via Putty).
11. Run:
    firstboot
    Y
    reboot -f