True ROM chips are by definition available in sizes slightly larger than similarly priced DRAM or SLC flash, it's probably cheapest memory to manufacture. And y

True ROM chips are by definition available in sizes slightly larger than similarly priced DRAM or SLC flash, it's probably cheapest memory to manufacture. And you would be surprised about how many megabytes of ROM are contained in Android/iOS devices (baseband code is often i mask ROM on chip, modern SoCs tend to have some kind of support core with code in mask ROM and also some ARM acessible mask ROM with things like "low-level" bootloader, if you count reading files from filesystem on MMC and relocating ELFs as "low-level"), even desktop PCs contain significant amount of mask ROM (CPU microcode, sometimes embedded controller code, microcode for various other chips, probably bootloaders for HDD controllers). Bottom line: flash is still more expensive than mask ROM, given enough volume (and by definition will always be).