Don’t use Multibit and get your Bitcoin out of MultibitHD

Yesterday I wanted to see how some of my Bitcoins were doing. I use Multibit HD 0.4.1. Suddenly MultibitHD showed the whole wallet being unconfirmed. That means that I couldn’t send any Bitcoins or that Multibit HD has lost its bookkeeping. I find this unacceptable. Who can work with a wallet that can’t do the bookkeeping correctly? So first start to fix the issue and then look for a better wallet.

I tried to repair the wallet several times but only a part would become confirmed. So, I still couldn’t get at my money. Even restoring from the seed didn’t help.

When you look at the issue tracker on Github, you see that a lot more people have issues. Especially the closed issue tracker, leaves people in the dust without their money. These issues have been popping up since October 2016 and I haven’t seen a warning since. A wallet project should do a good disclosure on any bugs it finds and issue a recommendation to stop using the wallet until the issue is found and dealt with.

I was able to extract my bitcoins by downgrading to Multibit 0.1.1 and do a repair of my wallet.

I became skeptical after the Multibit people sold the software to KeepKey. Also I needed to repair my wallet last year, which also scared the bejeezus out of me. Any project that produces a wallet that has a big button called “repair” shoudl do a better job. Those worries are now confirmed. Now getting the heck out of here towards a more sane client like electrum.

Photo: used and modified under Creative Commons license thanks to BTCKeychain

Visit to FOSDEM 2016

Screencapture from the FOSDEM home page
Screencapture from the FOSDEM home page

Here’s my report on visiting FOSDEM in Brussels last Saturday. The “Free and Open Source Developer European Meeting” is basically a mix between a 10.000 geeks, Free/Open Source Software projects, enterprise solutions and a sense of community descending on the Universite Libre Bruxelles (ULB) for a weekend. I really like FOSDEM for the atmosphere, interesting talks and it’s of course close by. I usually go for a single day to check out what’s happening. The talks range from showcases of:

  • Open source projects, (both large and small)
  • Using, designing and creating Open Source Software
  • Open Source protocols
  • Communities amongst projects and users
  • Maintenance of ancient hardware and software
  • Hardware, Internet of Things
  • Licensing and legal
  • Configuration management
  • Testing and Test Automation
  • Business aspects of Open Source Software
  • Lightning talks (You get 15 minutes of fame, answer 1 question and next.)
  • And a whole lot more.

You can also view all the lectures via the video archive, but it wouldn’t be the same.

IMG-20160130-WA0003This year FOSDEM occurred on Saturday 30 and Sunday 31 January 2016. I went together with 4 other people from hackerspace TDvenlo (Tjeerd, Gijs, Harm, Panos and Me) The main observation of the event was that the event is getting quite packed for a weekend, but still is loads of fun. We needed to drive to Brussels at 07:00h from Venlo because the introduction already started at 09:30h. The opening used to occur an hour later and this year there were 28 DEVrooms and almost 700 talks. (On twitter @FOSDEM and #FOSDEM) View photos for #FOSDEM on twitter via this link.

FOSDEM has grown quite a lot the last couple of years. It used to be 5000 visitors, I think it’s now more than 10.000 over the whole weekend. Maybe it should scale to more days. But then the University of Brussels (ULB) would probably stop hosting the event. It’s a really old building, but with a lot of atmosphere. Really like a Belgian organisation would take care of it. The scene looks crummy, but the event is great. More on future visits later.

My favourite talks for the day that I was able to visit:

  • Alidron: A distributed control system for the Internet of Things
    A nice talk about creating an autoconfigurable control system for IoT devices. With nice demonstrations and examples for hardware platforms. The really liked the Spirit 1 platform from ST. And they look like a good start if you don’t want to ess on the 2.4 GHz bands.
  • Inside H2O: Nice lecture on how to create a big MapReduce implementation based on Java across several JVM’s for really large datasets. I guess that H2O focusses on the researchers that need a simple interface and can afford extra hardware to run all their data in several JVM’s. Also keep everything as simple as possible. Because the people using it, do really complex stuff with H2O.
  • GNU Radio for Exploring Signals: A good technical in depth talk on GNU radio and processing FM radio. Brought back a lot of memories from University. What it can do and why it’s cool. I still have the rad1o from the Chaos Communication Camp 2015 lying around. Looks like a nice project to mess around with.
  • Libreboot – free your BIOS today!: This was quite an interesting talk from a free software approach. The most famous open source BIOS currently available is called Coreboot. But according to the Libreboot guys it has 2 problems. You need to build it from sources and it isn’t packaged. The other problems concerns that it uses binary blobs. The speakers was quite militant on using only Free software. Which limits the number of available hardware considerably. The speaker talked a bit like a sort of proto Richard Stallman. Which always reminds me: In the end Stallman was right. (But you didn’t have a working solution in the mean time.)
  • How to run a telco on free software: This was an interesting talk by Red Hat on how they try to use modern aspects of networking and virtualisation to replace the old big iron hardware that’s currently used by telecom operators. It is interesting because Open source is now invading telecom from the corporate and hacker side. The hacker side consisting of OpenBTS and creating a GSM network using pico cells and Ethernet. The talk also featured the “Value Trumpet”. Price and service used to scale linearly, but in the last 20 years they’ve moved apart. People expect more delivered value, for a lower price. Which makes this a really competitive market. So creating a new solution using virtualisation to replace all the old servers across different vendors and telco’s becomes a big deal.
  • TLS and SIP – what works and what doesn’t?: This talk became a really nice surprise. Although it came at the end of the day at 18:00h, it had an interesting speaker, interesting topic, small devroom where there was lots of interaction. The gist of the talk consisted of: SIP and TLS don’t work together because the client has different domain names via NAT and it would need a new certificate for each different subnet. XMPP does a better job of this by keeping the established connection open. WebRTC looks like how it should be done. There is still a lot of work to do, in order to get secure calls via internet on an open protocol that does not go via a telecom connection.

These where the talks that I visited and are worth going back for. However a lot of the most interesting rooms were occupied. It looks like ULB is becoming too small for doing this and keeping the event free/gratis. However, if you look beyond the talks and go for the ambiance, people, stands, obscure projects and lighting talks. It really is a one of a kind event.

I really like the smaller devrooms from time to time. You really see the interaction between people that normally meet online and now meet face to face. People don’t start calling each other names. Occasionally you have funny interesting interaction with the audience, because it’s half the project in a single room.

The stands were also great to visit. The Owncloud stand showed the fruits of their collaboration with Western Digital in making a home made kit using a Raspberry Pi and a 2.5″ 1TB drive for your own home server. There was also a stand with a home built laptop using 3D printed parts, and Allwiner A10 or A20 mainboard and cardboard.

Owncloud home server kit.
3D printed, Allwinner A10 module and cardboard laptop.
3D printed, Allwinner A10 module and cardboard laptop.

One of the other things I missed was Bitcoin and Blockchains. Only 1 of the 700 lectures mentioned bitcoin. On the other hand, decentralization, databases, high availability, privacy and communication were represented at FOSDEM a plenty. (View my presentation on the subject for more info.) With 10 billion USD pouring into Bitcoin and Blockchains, I think this will catch FOSDEM’s attention next year.

The main tracks are also cool, if they have an interesting topic and a great speaker. FOSDEM occasionally drops the ball by putting a mediocre presenter in front of 1500 people or the audio is crap. Which I think wastes a lot time for a lot people. The opening speech on Systemd was quite interesting, but the audio was too quiet. Which made it quite hard to follow the presentation. The talks by Andrew Tanenbaum and Eben Moglen from a couple of years ago remain engraved inside my memory. (Now I see on Twitter, that Stallman was present at FOSDEM. Too bad that I’ve missed it.) But FOSDEM shows that Open Source software is doing really well, growing and can do everything.

To accommodate the growth of FOSDEM and optimize our experience, this will probably become our strategy for visiting next year. Go to the devrooms that make FOSDEM great, enjoy yourself with other people and watch the rest on video. So that basically means go to the main tracks, obscure devrooms, the bar and the stands. Also try to avoid the material that you work with on a day to day basis. That makes sure that you learn new stuff. Sometimes I’m thinking: “We used to do it this way 10 years ago.” When the videos are online, organize a viewing event with the local hackerspace with some of the other people there.

All in all, we had a blast of a time at FOSDEM. We will surely visit next time in 2017.

Creating and configuring an E350 based media player running XBMC


This post briefly tells how I put together my media center using a mini-ITX board and XBMC.

The last couple of years I used an Asus O-play as a mediaplayer. While in 2010 it was really nifty, after 2 years it didn’t meet my needs anymore. The thing I really missed was watching Youtube movies on my TV and maintaining web-based radio station was also a PITA.

“Time for something else”, I thought in the end of 2012. Using XBMC on a small computer was still the hot thing to do back then. I tried XBMC on my laptop for 5 minutes and I was sold. Just do an apt-get install xbmc and a 6 year old laptop suddenly is a mediacenter. Well then it should also be possible to do it on a new cheap computer. Very cool open source stuff. At this moment I’m doing a software upgrade and that creates a great opportunity to write down how you build a nice home media center.

Here’s a brief intro on XBMC and how it works:

Note: This article might be late to the game after everybody and his uncle is now running XBMC from a Raspberry pi. But when I first build this system, there were still severe delivery problems with the Pi. Also I wasn’t convinced of the performance. Using a mini-ITX was the safest and fastest option. Also the Pi doesn’t run x86 code.

So these were my basic requirements:

  • The system shall get its content from the local network.
  • Doesn’t need an internal hard drive
  • Looks nice.
  • I choose what software runs on it.
  • Hardware should be future proof somewhat.
  • Low power during operation.
  • It should also run games and a normal desktop based on x86 binaries.
  • 100 mbit ethernet interface for receiving the content.
  • It doesn’t need to receive satellite television or record television shows.
  • It must show Youtube movies without too much hassle.
  • Adding and obscure radio station like or should also remain easy.

Figuring out the software part was not that hard. The Hardware was a bit more of a puzzle.


Choosing what hardware to use required some research. Using a mini-ITX form factor was a given and also I try to use AMD parts when possible. Fortunately a mini-ITX board with an E350 processor on it only costed around 60 EUR. I just needed to check if it had all the necessary interfaces

So just before Christmas I settled on the following parts:

  •  E350 based mini-ITX board A friend of mine has a E350 based laptop and is very pleased with it. This board has everything except the RAM memory on it.
  • USB flash drive with 8 gB of space For 10 EUR you have 8 gB of storage space to run the system on, it even is future proof with USB 3.0.
  • 4 gB of RAM memory Just remain on the safe side and be able to use 2 matched 2 gB modules to get extra speed from Multichannel.
  • Enclosure with PSU Since it will remain visible just next to the receiver and under the TV, You want something small and looking nice and with an external fanless power supply.
  • Keyboard and Mouse (wireless) I’ve mainly used the mouse during normal use. The keyboard is handy for gaming and troubleshooting.
  • 2 quiet fans, size 40 mm. The stock fan on the board are quite loud.
  • HDMI cable Connect the audio and video of the PC to the receiver/TV
  • Optical audio (optional) If the HDMI goes to the TV, you need a separate digital  audio connection towards the receiver.
  • Network cable Otherwise there is no method for delivering the content. I don’t trust wireless for media applications. Especially with Full HD blue ray movies.
  • USB stick for installation (optional) Installing the system can be done

Putting everything together went without a hitch. It’s just like a regular PC, but everything is smaller. The biggest hurdle was getting the fans quiet. The CPU fan worked flawlessly. The fan providing airflow through the enclosure provided a bit more trouble. The fan for the enclosure was mounted on the side and only fastened on the bottom of the chassis and the top side was resonating at a really annoying pitch. I was able to get it quiet by squeezing the power line for the fan between the fan and the upper lid of the enclosure.

Getting XBMC and installing

XBMC provides an image with Ubuntu i386 and the latest XBMC called XBMCbuntu. You can get it from their website here.

Just download the XBMCbuntu image and put it on a bootable USB stick using a tool like unetbootin.
note: You will only know if a USB stick is bootable after you tried it.

Start up the system using the bootable USB stick containing XBMCbuntu distro and install it on the 8 gB flash drive of the media center.

Future upgrades:

Getting the Android remote going.

note: photo’s will be added shortly.


#EMF2014 (Electromagnetic Field hacker festival 2014)

Last week Andrea and me (on twitter @jhaand and @awc_haandrikman) went to the hacker festival Electromagnetic Field in Milton Keynes, UK. Once again it formed an awesome experience. I will write a small synopsis of this event and post the pictures. We went to the UK on 2014-08-26 and arrived back on 2014-09-01. Because EMF only opened the camping field on Friday 0900h, we needed to stay somewhere else the day before. We used this opportunity to visit Saint Albans and raid some book stores in London.

I only had the camera of my Fairphone smartphone on me, so sorry for the quality. I also took some pictures from my twitter feed and included the source where possible. Enjoy.

The EMF website is at
The program was as follows:
Several news outlets did a piece on EMF: Vice, BBC and the Guardian.

Here is a short top 3 overview of the talks:

  • Day 1 (Friday, 2014-08-29)
    • Not Safe For Work: Industrial Control System Security / Corresponds completely with my work on High Tech Systems
    • Lightning Talks – Sign up at the Info Tesk! / The ‘spontaneous’ talk about AI immune systems for computers  was really interesting.
    • Showing keys in public / Just don’t or you’re pwned.
    • Gasman’s ZX Spectrum Chiptune Extravaganza / Here have some Dr. Who or src here.
  • Day 2 (Saturday, 2014-08-30)
    • Emojli: How we accidentally built an app and why we never want to build one again. / You start hacking and suddenly you’re harassed as a start-up. With VC and tech support and all. (Vice article here)
    • The 55th Flotilla (Live) With custom-built MIDI controllers & circuit bent lovelyness
    • Introduction to Information Security and Privacy / Good overview and you cannot be paranoid enough. Otherwise you lead a boring life.
  • Day 3 (Sunday, 2014-08-31)
    • Hexayurts, Distributed Infrastructure, and Maximizing Global Minimalism / Vinay Gupta on  roll: Kill the mortgage, Spotify’ize the building codes regulations and start building a nerd reich. (view here)
    • Why are computers so @#!*, and what can we do about it? / Unfortunately Technology won’t solve everything. Create a tool to offer an overview and the devs will stretch it to the limits. C should die for anything except bit-banging.
    • My Container Ship Holiday Slideshow / Welcome to the dystopian industrial world of container shipping in East China. Lot’s of stuff to see in nice navy grey with a Maersk logo.
    • Trials and tribulations of a badge project / Hardware is hard. Especially if you’re in the valley of death for 1500 SKU’s and need to organise a hacker festival parallel next to it.

For the rest there was a lot other cool stuff in no particular order:

  • Retro Game arcade by Awesome Retro
  • Nuclear Poker. The game for everybody older than 7.
  • Wifi and electricity on the camping site
  • The Festiyurt / mini quad dome hexayurt
  • Milliways: the restaurant at the end of the universe, offering Chili con carne at 0200h for free
  • Lots of interesting and creative people
  • Buy drinks with Bitcoin at the bar from a POS system that has Bitcoin integrated.
  • Enough space to place all your tents ‘n stuff
  • Awesome chip tune music
  • Blacksmithing workshops
  • Laser cutters
  • Lightning Talks
  • Being still able to take in information and find the correct word-thingies, while being sleep deprivated.
  • Able to stand the portaloo’s.
  • And many more stuff which would make this article too long.

Finally I want to thank the following people for their total awesomeness: Andrea Haandrikman, Vinay Gupta, @ian_willy + kids, @Herx, @Frabcus, @spongefile, @artied and @jonty.

update 2014-09-07: Added some external links and mentions from news sources.

The day we fight back banner added

tdwfb_headerTomorrow an internet wide action against surveillance will take place. It’s called “The Day we Fight Back” A lot of sites will add a banner tomorrow to show we have had enough of everybody spying on us and harvesting the data about us.

More info:

You can add an plugin to your wordpress site very easily. Just add new plugin on your website. Enter “NSA” in the search field and the plugin comes out on top. Install and activate the plugin.  Changing the settings of the plugin, can be found the global under settings.

Ohm2013 retrospective

My body has now almost caught up from the exhaustion and my thoughts are a bit straightened out after #ohm2013.  So now is a good time to start writing about it.

I had a great time at Om2013. Always something to do and lots of people to talk to. So updating my blog was not really an option during these amazing days. Fortunately al lot of tweets went into the Twittersphere to record some of the events.
So a week has gone after the event and my spinning head is coming to rest somewhat. Like a friend of mine said: “Interesting how you can suck up all that information, communicate with others while suffering from  sleep deprivation.” The most scariest thing about the event was driving back home van Ohm2013 back to Venlo with only 3.5 hours of sleep. The most beautiful surprise was the Bach recitial by Kimiko Ishizaka.
All in all it was a great event, met a lot of interesting people, heard interesting talks and enjoyed myself tremendously.I think al lot of good and interesting hacks will result from it.

I really look forward to the next event. Whichever that will be.

I try do a couple of postings the coming days. I think with the following subjects: Photo’s, Interesting talks and ideas I’ve come up with.


Arrived at OHM2013

This afternoon I drove towards OHM2013. Of course it started raining in the afternoon and did’t stop until 10 o”clock. I was able to put my tent up and make me some dinner. Almost everything got wet this afternoon, but I was able to pull it together and set everything up for the coming days.

It’s now almost midnight and it’s great to be back here. The atmosphere is already really good. The Blinkenlights are operating and give you the feeling this is something special.

Unfortunately the bar has closed down now.