i have try this on ubuntu linux with amdgpu 18.40 with 5 rx470 modded bios, previous mining with claymore 15 is ok. after 352 cannot mining any ethash miner app. --platform=1 not work, vga on board not on and not monitor connect.

./teamredminer --platform=0 -a ethash -o stratum+tcp://eu1.ethermine.org:4444 -u 0x06030e479c965aDE02e10814355309Ac9c2fb670.myriglab -p x

          Team Red Miner version 0.7.8
[2020-07-31 20:12:37] Pool eu1.ethermine.org: Ethermine ethash auto mode detected, setting --eth_stratum=ethproxy
[2020-07-31 20:12:37] Failed to probe OpenCL device idx 0 on selected platform 0, will be excluded.
[2020-07-31 20:12:37] Failed to probe OpenCL device idx 1 on selected platform 0, will be excluded.
[2020-07-31 20:12:37] Failed to probe OpenCL device idx 2 on selected platform 0, will be excluded.
[2020-07-31 20:12:37] Failed to probe OpenCL device idx 3 on selected platform 0, will be excluded.
[2020-07-31 20:12:37] Failed to probe OpenCL device idx 4 on selected platform 0, will be excluded.
[2020-07-31 20:12:37] Successful clean shutdown.

my clinfo is

Number of platforms                               1
  Platform Name                                   AMD Accelerated Parallel Processing
  Platform Vendor                                 Advanced Micro Devices, Inc.
  Platform Version                                OpenCL 2.1 AMD-APP (2686.5)
  Platform Profile                                FULL_PROFILE
  Platform Extensions                             cl_khr_icd cl_amd_event_callback cl_amd_offline_devices
  Platform Host timer resolution                  1ns
  Platform Extensions function suffix             AMD

...