A Self-Directed IRA can be funded with new contributions from current taxable income, a transfer from another IRA (trustee-to-trustee transfer), or as a rollover from an old employer 401(k). Right now, it is not advised to do a Roth Conversion on the Rocket Dollar platform unless you pay for both a traditional IRA and Roth IRA account setup. Roth IRAs can receive Roth IRAs or old 401(k) plan Roth dollars.
For a Traditional IRA
A Self-Directed Solo 401(k) can be funded with new contributions or rollovers from other qualified plans. Unfortunately, you cannot roll over Roth IRA dollars into a Solo 401(k) Roth plan.