Jay's Technical Talk » hdhomerun

MythBuntu doesn’t support AutoIP

Jay — Tue, 22 Dec 2009 13:18:51 +0000

MythBuntu (and Ubuntu I assume) don’t support the AutoIP standard.
(Auto IP is basically a way for devices to form ad-hoc networks…if you don’t have a static IP, and are not assigned a dynamic IP via a dhcp server, you try out a random address in the 169.254.x.x network (255.255.0.0 netmask) and as long as ARP doesn’t report a conflict, you now have your IP!)

Windows, and the HDHomeRun devices support this, but MythBuntu 9.10 does not. So, I’m back to using firestarter to easily configure my MythBuntu box to assign the HDHomeRun an IP address via DHCP.

Discovery Error 4001 : Silicon Dust HDHomeRun error

Jay — Sun, 20 Dec 2009 22:43:49 +0000

I was in the process of changing out my MythTV backend machine, and when configuring the new machine, I took a look on SiliconDust’s website for a firmware update for my HDHomeRun (HDTV Network tuner box). I hadn’t updated it since late 2008, and sure enough, they were five or six firmware versions farther along. (Up to 20091024 to be specific.) So I upgraded the box using the newest version of the hdhomerun command line utility under linux. Everything went fine until the HDHomeRun rebooted. After that point, the utility said that an error occurred discovering the HDHomeRun! I tried booting into windows to try out the windows software, but it also could not discover the device, and gave me this ominous message:

Discovery Error 4001: Please email support@silicondust.com

Apparently this is a known issue, as the troubleshooting document from SiliconDust says: “The HDHomeRun requires an additional configuration update. Email support@silicondust.com, or file a trouble ticket; be sure to include the device ID listed on the bottom of the HDHomeRun and “Discovery Error 4001” in the message.”).

From reading other blog posts, it appears that the fix is for them to send you an executable file. You run the file, and it fixes your HDHomeRun over the network. I can accept this, but I’m not happy with having a firmware update freeze my HDHomeRun (on a Sunday, with the earliest support response 12 hours away). As a last ditch effort, I plugged the HDHomeRun back into my current MythTV computer, and was surprised the find that it still worked! Apparently, as long as MythTV is already configured, things are still working, even though I can’t discover the device!

When looking into this, I found what I think is the problem. The firmware update has blown away the last 24 bits of the device’s MAC address. When it asks for a DHCP address, you can see that the last three bytes are all zeros: (after the 00:18:dd)

Dec 20 16:50:31 elvira dhcpd: DHCPOFFER on 192.169.1.2 to 00:18:dd:00:00:00 (HDHR-FFFFFFFF) via eth0
Dec 20 16:50:32 elvira dhcpd: DHCPREQUEST for 192.169.1.2 (192.169.1.1) from 00:18:dd:00:00:00 (HDHR-FFFFFFFF) via eth0
Dec 20 16:50:32 elvira dhcpd: DHCPACK on 192.169.1.2 to 00:18:dd:00:00:00 (HDHR-FFFFFFFF) via eth0

So my suspicion is that the executable that SiliconDust will (hopefully) be sending me on Monday re-programs the devices MAC address for you. (and possibly fixes other configuration bits that also got blown away?) In any case, I wish they had a universal fixer program that I could download from their website now, when I had the problem, instead of having them custom make me one and then send it to me. (I wonder why they don’t trust me to enter my device ID myself?)

Update: 24 hours later they sent me a windows executable (which came with a cygwin dll file) that re-set and fixed my HDHomeRun.

Waiting for a HD HomeRun before starting the MythTV backend

Jay — Sat, 14 Feb 2009 18:59:38 +0000

My mythtv box uses a SiliconDust HDHomeRun external network based tuner. Every so often (1 out of 5 boots) the network subsystem does not get started up before the mythtv-backend daemon. This causes an error where the mythtv-backend does not find the tuner, so it can not record any shows.
[I have my HDHomerun set up with an ethernet crossover cable directly plugged into the MythTv box, which is doing the DHCP setup of the HDHomerun directly, as opposed to having an external home router that does this. I suspect that this is the cause for the race condition.]

To fix this problem, I created a script (wait_for_hdhr) that will wait for the HDHomerun device to be found on the network before it exits. I call this script from inside the /etc/init.d/mythtv-backend script just before it starts up the mythtv-backend.

Now, about 1 out of 5 boots, instead of failing to connect to the tuner, my Ubuntu 8.04 based mythtv box will “pause” at the booting status bar for five to ten seconds. Then it drops to the text based boot-up messages and displays 8 to 12 “No HDHomeRun found yet…” messages before continuing with the bootup procedure after the network is initialized and the HDHomerun device is found.