Before proceeding ensure you have backups of your wallet.dat. Use the file backup option in this guide.
This procedure will ‘Dump’ your existing Syscoin 2 wallet via BM 1.2.x into your public folder, and ‘import’ this wallet into Syscoin 3 via Syscoin QT 3.0.x from the same folder. Your wallet will then be upgraded and safe to use on the new Syscoin 3 chain.
Download and run the latest Syscoin QT and allow it to fully sycnc.
( If you have already installed Syscoin 3.0.x then you need to ensure it is empty and has the HD symbol in the bottom right hand corner, if not you will have to go to the syscoincore data folder and rename wallet.dat to oldwallet.dat. For this procedure you need an empty HD wallet)
Whilst waiting we will ‘Dump’ your wallet from BM 1.2.x
Open BM 1.2.x and unlock, BM does not have to be synced to carry out the dump operation.
Open Console (this is found by clicking the small person-shaped icon in the top right corner)
Go to /dumpwallet and press ‘Get’
Then press ‘Try It Out’
In the ‘filename’ enter (nothing else no quotes).
xxxxx is your username
If successful you will see ‘Null’ in the response body
Navigate to C:\Users\Public and you will see the ‘sys2dump’ there.
Navigate to /Users/john/Public/ and you will see the ‘sys2dump’ there.
You can now close BM 1.2.x if successful.
Now return to Syscoin 3.0.x which should have finished syncing.
Open the Debug console Tools-Debug Console
this time including quotes.
xxxxx is your username and no quotes
Press enter and you will get the Importing message, wait for this to finish.
Your funds should now appear in Syscoin 3.0.x. Please ensure you encrypt your wallet (Settings) and back it up (File). With this QT it makes automatic backups every time you open it, you will need to delete the ones made before you encrypted it. Tools-Show Automatic Backups.
Because your addresses where not created by a HD wallet it is best to send them to a newly created address within QT 3.0.x, if you are sending your whole balance you need to tick the deduct fee box. If you are unsure just send 1 sys as a test.
This tutorial is written by JohnP and the Original source can be found here.