Lothean:
Is it clear enough or my English is too broken ?
Your English is fine.
You have provided a lot of useful additional information in that Reply.
One thing you have not told us (IIRC) is how many steps per second you have been trying with the DRV8825 and motor 1.
Assuming it is not working even with a very slow step rate then it may be that it requires more current and the suggestion of @outsider may help.
When you try to drive motor 1 with the DRV8825 does it become more difficult to rotate the motor shaft with your fingers? If so it would suggest that something useful is happening.
...R