Whats the difference? The heart sutra seems to equate the two. Is it just matter of viewpoint? Where does the conditioning of conditioned phenomena come from?
There are a few positions. My own understanding of what makes the best sense, is that found in Nagarjuna's commentary to the Prajnaparamita:
《大智度論》卷31〈1 序品〉：「離有為則無無為。所以者何？有為法實相即是無為」(CBETA, T25, no. 1509, p. 289, a16-18)
Apart from the conditioned, there is no unconditioned. Why? Because the true nature of conditioned dharmas is the unconditioned.
Now, as we know, the nature of the conditioned is that whatever is subject to arising is subject to cessation, dependent origination. This is the unconditioned. Also known as dharma-dhatu, suchness, dharmata, etc.
Knowing this, one abandons "self-view". This is stream-entry for sravakas, and non-regression for bodhisattvas.
Continuing to see this nature of dharmas, the bodhisattva amasses the other conditions for full awakening. Once amassed, they end the defilements, and attain the utmost, right and perfect enlightenment.
This is distinct from the hinayana teachings on the conditioned and unconditioned, where both are distinct dharmas. ie. matter and mind, etc. are conditioned dharmas; nirvana (etc.) are unconditioned dharmas. The two types are distinct and basically unrelated to each other.