I cannot find clear information about that :
Does LPUART peripheral on KL17Z256VLH4 support Ring buffer (FIFO) ?
The MKL17Z4_features.h file set by default FIFO to 0
#define FSL_FEATURE_LPUART_HAS_FIFO (0)
Setting this feature to 1 generate error in compilation
../drivers/fsl_lpuart.h:153:32: error: 'LPUART_FIFO_RXEMPT_MASK' undeclared here (not in a function)
So I guess that KL17Z does not support it but I want to be sure.