Hawaii GPUs need modified kernels to continue working with the larger DAGs, we just haven't had the time to make it. For now you can use -clkernel 0 to use the generic kernels - they will be slower, and you also should set -mi 10 or -mi 11 to decrease the stale shares. Another option is to mine ETC, where the DAG is much smaller but with the current profitability you are probably better with mining ETH with generic kernels.
If this is true then why gminer or nanominer still works on my R9 390 and without any speed reduction (30mh/s) on ETH?
Thanks, man, you saved me from mining ETC with these cards! I've spent the entire day and before that more days looking for a miner that can work with all my 390's for ETH with no luck on smos. The miners either don't load DAG on some cards, or simply won't hash. Gminer for example was hashing at full speed but with 0 accepted shares. For some reason I've missed only nanominer but after reading your post I decided to give it a try. For my surprise it worked well for all my 390's. My internet is dropping too much today and I can't judge how many are the stale shares, but it seems ok. I don't know if giving a root access will make the miners work and recognize the cards. The other problem is that with a bios mod with 150-200mV undervolt the cards crash with all miners except Claymore. If I put the default clocks in the OC tables somehow the clocks lower a bit, the hash drops with 1-2 Mh, but the cards are stable and won't hash. May be a lame solution, but these cards are power hungry with 330W from the wall and need that undervolt. After the bios mod the consumption drops to 220-250W, may be even less. I am not sure, since I didn't measure the consumption of the MB with a CPU load without the cards. Anyway, hopefully phoenixminer developers soon will fix the issue with these cards.