If the data stored in the physical memory has been encrypted using a randomly generated secret key by the memory controller on the CPU, it should be impossible to generate an exact target data pattern in the victim even when the aggressor and victim are in the same enclave.
That in itself isn't sufficient to guard against all attacks, because the memory enclaves don't provide data integrity, only encryption. So if all you're trying to do is to change a victim's boolean that controls whether you have e.g. root access, then changing that boolean from false (0) to true (any non-zero value) is going to succeed with high probability despite the encryption.
Still, maybe there's an angle here that can help put an end to Rowhammer once and for all in a few hardware generations?