CHANGELOG:

@first, I sketched up a solution for a small BGA package 64Mbit  NOR FLASH w. QSPI interface, and although the MCU datasheet mentions something about low_voltage pins, the 2v rating of that IC makes the interface too dodgy.

So I have settled on a larger 128Mbit (16MB) external QSPI FLASH IC rated for 3.6v.