After messing up my GuruPlug (writing the wrong U-Boot to my GuruPlug, and thus ending up with a bricked device), I finally managed to make it run again. I also started to test Amahi, which looks vers promising.

I wrote two new articles, one on how to Unbrick (flashing with JTAG), and one on how to boot from microSD. However, those two articles are only written very quickly. Hopefully they are useful for some of you, since the described information was hard for me to find anywhere else.

Finally, my semester is over and I have time to continue my GuruPlug setup. Today I connected my DAS via eSATA to my GuruPlug. I hope this will give some more speed to file transfers, I will run some tests later.

I have an important update on the silent cooling post. My fan sometimes stopped running and needed some help to run again. Please read the warning with further information and updates.

UPDATE: I have replaced the resistor with a red LED. Read more in the updated post.

The hardware modifications are finished and I even did some temperature measurements to make sure everything works well. The following articles are new:

• GuruPlug Fan: Some technical information about the fan
• Open the GuruPlug: Just some information on how to open the GuruPlug and a picture of the inside
• Improved cooling: How to place the fan in a better position
• Silent cooling: How to slow the fan down to decrease noise
• Temperature measurements: Some temperature measurements with different setups

After a while with no new blog posts and no new articles, I am back with some hardware modification to make my GuruPlug more quiet. The best idea I found is the idea from this forum thread. I like the idea mainly because the inside of the GuruPlug is not modified a lot and also the appearance does not change a lot. In addition, the airflow is quite perfect since it flows through the whole plugcomputer cooling all the components.

I just started the modification and of course documented with pictures for every step. The only thing I have to solve now is if I use the current fan from the GuruPlug (at lower speed) or if I should order a different one with sleeve bearing (should be more silent). I have to run some tests there and I'll post my results as soon as possible. The article can be found here.

I am back from vacation but sadly I have to announce some bad news, but don't worry, the good ones will follow.

The bad news first: I still did not get my GuruPlug back and Global Scale has removed their statement about the upgrade kit which should, from the date of the release of their news, be ready "in the coming weeks (not months)". The mentioned upgrade kit should include a small fan and the equipment to connect it - on request and free of charge. I am wondering what the removal of these news could mean, but the good news followed soon after. Not from Global Scale, but from NewIt (where I got my GuruPlug). NewIt has two despatch dates, September 10th and 15th. A few days later the units should arrive in the UK and forwarded to the customers. However, they are still waiting for the upgrade kits or any news about it. Let's hope it all works out. If it does, I should get a new/fixed GuruPlug at the beginning of October.

GlobalsScale Technologies, the provider of the GuruPlug and the Sheevaplug, made an announcement a few days ago regarding to the GuruPlug overheating problems. Unfortunately, there will be no replacement of the daughter board as stated in my last post. They came to the conclusion that the main problem is the load on the CPU which can be caused by running the GB-Ethernet, Wireless and other interfaces at the same time. Their recommendation is to run the network interfaces at 10/100MB to reduce the CPU load. In a few months, they will release a "Professional Upgrade Kit" to solve the problem. How this upgrade kit is going to look like is not published yet.

Some users of the Sheevaplug also faced a problem, but with the power supply. It is now possible to buy a new power supply and replace it with the old one. Here is a guide on how to do the replacement.

Many people face the problem that their GuruPlug gets very hot. There have been many attempts to cool the device by adding a fan, a heat sink, or as I solved it by using an external fan. However, this can't be a good solution since people want to buy a device which works and which does not have to be modified. The developers at GlobalScale are now revising the GuruPlug. So far, it is not sure how the replacement will be realized. Either the people with a faulty unit will just get a new one, or the customers/resellers will get a replacement board (the daughter board) with a new power management chip (and most likely some other improvements).

As mentioned previously, my USB-ports are broken and my GuruPlug gets quite hot. Luckily, the reseller where I got my GuruPlug (NewIT from the UK) is very cooperative and they will advise their customers as soon as GlobalScale defines a delivery date for the replacement board. This means that I can keep my GuruPlug until they get the 2nd batch with the applied upgrades, and I will get a new one from the 2nd batch. Right now, I actually do not have much time for developing because I have my semester finals within the next three weeks, but whenever I have some time, I'll move to the next step: Using the GuruPlug as Gateway between the ADSL-router and my home network. The main thing I am struggling here is to find the right setting for the ADSL-router and to understand the IP-forwarding and DHCP-functionality for the LAN, but since Debian has it all within the packet management, it is only a few commands away ;)

To see if my GuruPlug works fine (since I heard about rebooting issues and network problems), I just let it run over night, of course with my USB-fan running to assure a good air flow. The next day, everything was fine as far as I remember but when I tried to connect to my USB hard drive, I figured out that my USB ports don't work any more. There is no 5V power and also an external USB-drive does not work, neither does the SD card.

Now I am wondering what could have happened. Did the constant 80mA of the USB-fan destroy the USB-interface? That should be impossible since the USB specification requires a current up to 500mA, and it's running on my PC's USB for a few days now without problem. Is it a heat problem which made my USB die? or did I mess up some configuration? Since I do not want to loose warranty I did not open my plug yet. It might just have burned some part which is easily replaceable, but if I can't fix the problem without opening the case, I will first try to return it before I do anything else.

To figure out if I messed up the configuration, I decided to re-flash my GuruPlug. This is also a great possibility to get to know the boot process better and get some insight into the file system. The tutorial I am following is the reflashing-tutorial on plugcomputer.org. It seems to work, but I am having some troubles getting the root file system to the plug using tftp. Here are my experiences with tftp and the installation process. I also added a short tftp-tutorial.

Cooling your GuruPlug might be an important criteria if you have one of the recent ones. It seems to be a problem with the design since there is no heat sink and not enough space for air exchange. I hope we would get further information from GlobalScale. It seems like they are redesigning a few things. This post shows some e-mailed information from GlobalScale.

Here is another interesting thread on the NewIT forum, since it describes some problems people have and there are also some solutions with some interesting pictures (it seems like you have to be logged in to see the pictures...).

My solution so far is to cool the GuruPlug housing from the outside with a 12cm 12V fan using the 5V of the USB-interface. Of course, I share my idea and wrote a small tutorial about my USB-fan.