...may want to avoid doing opkg update && opkg upgrade. (For the TL;DR version see last line) I've found what appears to be a pretty major bug (for Tomato users anyway, given our kernel age and all that) in libpcap 1.3.0: Code: root@gw:/tmp/home/root# tcpdump -i vlan2 "tcp and port 80" tcpdump: vlan2: SIOETHTOOL(ETHTOOL_GTSO) ioctl failed: Invalid argument Details are in the below Entware ticket. Please start at comment #3 (the previous comments are about the fact that someone rebuilt tcpdump to link to libpcap 1.3.0 but didn't increase the tcpdump package number, which is irrelevant to the issue I'm talking about here): http://code.google.com/p/wl500g-repo/issues/detail?id=180 The bug appears to be a regression/broken logic decision in libpcap 1.3.0, which has since been fixed in 1.4.0 (which is not available on Entware yet). Previous versions of libpcap do not have this problem. I am absolutely certain ryzhov_al will look at it and fix it/work with me on getting it fixed. TL;DR -- if you run Entware and have software that uses libpcap (opkg list-installed | grep libpcap, and if there's results, opkg whatdepends libpcap to get a list of Entware programs installed which would be impacted), you may want to avoid upgrading your Entware tools until this can get worked out. If you already are using libpcap 1.3.0 and things using it are working fine for you, then great (that just means the programs you're using aren't trying to make use of the libpcap API that issues the ETHTOOL_GTSO ioctl). P.S. -- I'm still on hiatus, but this was major enough that I wanted to make a post and let folks know.