There seems to be some confusion about registering your EOS tokens. I experienced a bit of this confusion myself. I used MyEtherWallet to contribute to the eos token distribution and managed to claim my tokens no problem - but it wasn't clear how to go about generating an EOS key pair and how to map the ethereum address containing the EOS tokens to it.

I found a couple posts that recommend using this third party app to generate an EOS key pair. For me using a third party modified app didn't feel right so I used the EOS Token Distribution App on the eos.io website.

Please look at https://eos.io/instructions under the "How to Participate" heading. To make your life much easier Use the Recommended configuration! See below:

Install the meta mask chrome extension Open up the EOS Token Distribution App

If you have properly configured meta mask then you should see the following after clicking on the "EOS Token Distribution App" button:

As you can see there is no EOS key currently registered to this ethereum address. To map an EOS key to this ethereum address:

Click on Generate EOS Key

Back up the private key in multiple places! You cannot recover the private key and you need it to access your EOS tokens when the token distribution ends Copy and paste the private key into the field like so

Click the I have safely backed up my private key button This executes the register contract which will cost you a little bit of ETH so I recommend only doing this once...unless you have to update your key mapping for some reason. You will see a Meta Mask transaction window pop up that looks like this:

Submit the transaction. When the registration process has completed successfully you should see something like this:

The important point here is that the EOS Public Key field now has an EOS public key in it. Which tells me that this ETH address is mapped to that EOS address.

Oh, if you have purchased your tokens on an exchange. You can simply send your EOS tokens to the address that you registered through the process outlined above.

I hope this helps. I can't stress enough Go with the EOS.IO Recommended Configuration for participating in the token distribution! It really makes things a lot easier than trying to participate with MyEthWallet.