One of the great advantages to Android is the freedom developers have when submitting apps to Google Play. Because they can submit what ever app they want we see apps pertaining to bitcoin and many other crypto currencies. Where companies like Apple used to accept apps about bitcoin, they stopped for some reason. Now Apple only allows Dogecoin apps.
Another advantage to Android is the freedom you have with the system itself. iPhone users will never get to experience a custom built iPhone ROM, nor will they ever be allowed to modify their existing ROM.
Because of these advantages with Android we can modify the system to act with one purpose. This is great with older Android devices that you can buy off of ebay for about $20.00. And in the example I’m using in this blog you wont need to worry about if the ESN number is good. I chose to make my old phone into hardware based bitcoin wallet since a very common hardware wallet on the market costs over $100.00 and only store crypto currencies.
The first thing we will need to do is make sure our Android Device is rooted. If so we will start by first removing many apps such as the dialer app and messaging app, and all of the email apps. However I will state before you go any further you should backup your current ROM.
We can do this with Android Terminal Emulator or using the Android SDK by typing the following.
After we have removed all apps that we do not need we will then remove any updates to the apps we just removed. to do this we will type the following.
We can now clear our Delvik Cache by typing the following.
Depending on your ROM you may have additional fonts that you can choose from. Since we will only be using one lets delete the ones we aren’t using. To do this we will type.
Repeat the above until all fonts except for the current one your using have been removed.
Now lets remove all the sounds.
rm -R media
Now lets check how much space we have freed up by typing.
Now lets go to Google Play on our computer. Unless you chose not to remove the Google Play App on Android. And install the following apps to the device.
Now apps that don’t ship with the rom get installed to the /data/apps directory. Since we are making this to be custom rom we will want it to go in /system/apps directory. So to do this we will type the following.
mv /data/apps/com.mycelium.wallet.apk /system/apps/mycellium.apk
We will also want to clear our delvik-cache again. To do this we type the following.
Restart the device and your done. You now have a hardware bitcoin wallet that costs you $20.00. Plus you can make it do more then the hardware wallets selling for $100.00