My TP-LINK WR841ND v8.4 works perfectly. Have tun0 to USA.

I get:
Unknown package ‘kmod-tun’.
Collected errors:
* opkg_install_cmd: Cannot install package kmod-tun.

Need help please!

1-. to be cleared to make space?
2-. How to configure openVPN client on this router?

PS: if you want some hosting space to share your firmware with all of us, I can provide it :-)

HOW TO (roughly):
Get the ImageBuilder file from http://downloads.openwrt.org/attitude_adjustment/12.09/ar71xx/generic/
+ necessary packages to compile everything. For details check http://wiki.openwrt.org/doc/howto/obtain.firmware.generate

Generate image using the make command. Pay attention to the selected packages here:
[cc lang=”bash”]
make image PROFILE=TLWR841 PACKAGES=”kmod-tun liblzo libopenssl openvpn-openssl wol etherwake dnsmasq dropbear firewall iptables iw kernel kmod-ath kmod-ath9k kmod-ath9k-common kmod-cfg80211 kmod-crypto-aes kmod-crypto-arc4 kmod-crypto-core kmod-gpio-button-hotplug kmod-ipt-conntrack kmod-ipt-core kmod-ipt-nat kmod-ipt-nathelper kmod-leds-gpio kmod-ledtrig-default-on kmod-ledtrig-netdev kmod-ledtrig-timer kmod-ledtrig-usbdev kmod-lib-crc-ccitt kmod-mac80211 kmod-nls-base kmod-ppp kmod-pppoe kmod-pppox kmod-tun libc libgcc libip4tc libiwinfo liblzo libnl-tiny libopenssl libubox libubus libuci libxtables mtd netifd -opkg ppp ppp-mod-pppoe swconfig ubus ubusd uci wpad-mini zlib ntpdate curl”
[/cc]
NOTE: OpenVPN might require valid system time (or else you’ll get a certificate error), hence I added the ntpdate package. There is other ways but adding “ntpdate -u ” to the crontabs and to /etc/rc.local will do the trick.

A “minus” in front of the package means it was explicitly deselected.
Using above packages, the image will NOT include the opkg package manager but there won’t be much space left on the device anyway (less than 100K for me). You can play around with it and maybe kick out stuff like the PPPoE and curl packages, but from my experience you won’t gain much free space, certainly not enough for the whole LUCI webinterface.

IMPORTANT! Make sure you keep the essential packages so you don’t brick your router. Only way to unbrick is to solder a TTL to USB cable to your router board (which is a good idea anyhow).

After running the make command, firmware files can be found in the “bin/ar71xx” directory. In case of a WR841N v8 this would be “openwrt-ar71xx-generic-tl-wr841n-v8-squashfs-sysupgrade.bin”.
IMPORTANT! Make sure the image file size does not exceed 3670020 bytes. Anything above that made the /overlay filesystem use RAM and hence any changes you make will be lost after a reboot.
If the file gets too big you might even brick you router.

First time accessing your router:
[cc lang=”bash”]
telnet 192.168.1.1
[/cc]
Use “passwd” to set a password for the root account. After that, telnet will get disabled and you can access it using SSH.

Flashing an image manually (no webinterface):
If you want to flash an image without the webinterface, you will have to do it manually.
Telnet / SSH into your device and place your the new image file in the /tmp folder (no space anywhere else).
Enter:
[cc lang=”bash”]
mtd -r -e firmware write MyImageFile.bin firmware
[/cc]

ADVICE:
As mentioned before, it is a good idea to have a TTL/ Serial connection in case you brick your router. For more details see: https://forum.openwrt.org/viewtopic.php?id=33906
It’s a good idea to check out all the links I’ve put here and study them well BEFORE you try anything.