Appreciate your help, it works like intended and I was able with your explanation to get going.
Tricky part was the real understanding of the translation from
4020bf8a: c40000 extui a0, a0, 0, 13
4020bf8d: 3ffe87 bbsi a14, 24, 4020bfd0 <divide+0x34>
To the address
3ffe87c4
Due to the (I think) disassembling sometimes "reversing" the little endian mode and display in big edian.
Solved that by looking at the objdump -s of the irom0.text ouput.
Limited the output of all -s to objdump -s -j.rodata and now up to scanning/searching the files automatic.
Herman