Resolved! STM32H7 HAL library: HAL_SPI_Transmit_DMA is referencing RX side DMA handle for packing mode check
There is a packing mode check in Drivers/STM32H7xx_HAL_Driver/Src/stm32h7xx_hal_spi.c, function HAL_SPI_Transmit_DMA around line 1464, that is referencing RX side DMA handle:1464 /* Packing mode management is enabled by the DMA settings */ 1465 i...