DA14586 SPI Boot

I want to use an MSP430 configured as an SPI Master to boot the DA14586. (using pins P2_0/SPI_CLK, P2_3/SPI_EN, P2_4/SPI_DO, P2_9/SPI_DI as specified in the datasheet). When the MSP430 sends the SPI Master boot protocol (according to UM-B-079 Software Platform Reference Table 40) I don't get a response (I'm expecting ACK or NACK for bytes 3 & 6). Instead, the DA14586 switches to SPI Master and searches for external flash modules (according to the booting sequence in UM-B-079).