* If you already have a v2 wallet installed on your Raspberry-pi device, you should already run it from /home/user/.pengolincoin. Stop it and wait to be sure it's completely stopped.
* Then create a new v3 folder (for example: /home/user/.pengolincoin-v3) and copy/paste you wallet.dat from v2 folder to new v3 folder.
* Then run the v3 app like this in a console (or create a launcher on your desktop for example):
./pengolincoin-qt -datadir=/home/user/.pengolincoin-v3
This way it will not mix v2 and v3. Be sure to replace user with your real user name.
* V3 will "update" you wallet to HD wallet... follow the instructions
* Then it will sync from scratch. From there, you're good