Would a chip (such as a CPLD/FPGA) implementing mmc/sd be an option? It could host a chainloader with PCIe support and serve as a kind of rom. Also, is there a

Would a chip (such as a CPLD/FPGA) implementing mmc/sd be an option? It could host a chainloader with PCIe support and serve as a kind of rom. Also, is there any work on kernel level x86 emulation on arm for expansion roms?