for row 16, pls refer to:
"The memory vendors often do not offer so many variants of single-channel memory
devices. As an alternative, a dual-channel device with only one channel connected
may be used. For example:
A dual-rank, single-channel device with 16-row address bits has a density of 16Gb.
If such a device is not available at the chosen supplier, a dual-rank, dual-channel
device with 16-row address bits can be used instead. This device has a density of
32 Gb however since only one channel can be connected to the SoC, only half of the
density is available (16 Gb).
Usage of more than one discrete memory chips to overcome market constraints is not
supported since only point-to-point connections are assumed for LPDDR4."