This tiny project allows converting ESP32 ROM blob to ELF file with symbols. It is derived from esp-elf-rom project.
First, you need a ROM image. Either you can use file bootrom.bin in this repository or you use esptool.py to download a ROM image with command:
esptool.py --chip esp32 -b 921600 -p /dev/ttyUSB0 dump_mem 0x40000000 0x00064ae0 bootrom.bin
Once, you have the ROM image, use simply command
make
to produce an ELF file bootrom.elf that can be used with command
xtensa-esp32-elf-objdump -d bootrom.elf > bootrom_disassembled.s
to disassemble the ROM code.