IIM-42652 - how switch to 4wire SPI mode?

I have stm32 and IIM42652, and 4 wire SPI.

I need switch IIM42652 to spi mode.. I use 1.5Mhz clock.

In sec.12.3 of datasheet "Upon bootup the device comes up in SPI mode."

I try record (16) to reg17 - for switch "spi mode" to mode 1,2 ( what mean it ?) - not effect, i can't read any non-zero default register/

For mpu6000, (for example), i for first inititialization write (16) to reg17 and next all ok.