VP8 decode fails on i7-8550U

I try to decode vp8 encoded file with api1x_core\legacy-decode example. The only change i made the example is change mfxDecParams.mfx.CodecId to MFX_CODEC_VP8 and include vpl/mfxvp8.h. The output of the example is the following:

Implementation details:
ApiVersion: 1.35
Implementation type: HW
AccelerationMode via: D3D11
DeviceID: 5917/0
Path: C:\WINDOWS\System32\DriverStore\FileRepository\iigd_dch.inf_amd64_c34fd594e40bf436\libmfxhw64.dll
Error initializing decode

MFXVideoDECODE_Init returns, with MFX_ERR_UNSUPPORTED. According to Intel's documentation VP8 decoding is supported on this cpu generation. Why MFXVideoDECODE_Init fails?