What does objdump want from me?

Question

reverse engineering

Good day.
I understand with dsm from synology. I downloaded the latest firmware version, unpacked it, found nginx and crowds of cgi scripts there. it turned out, almost all - elf.
I'm trying to reverse.
objdump says

----- ----/hda1/usr/syno/synoman/webman $ objdump  -f pingpong.cgi 
pingpong.cgi:     формат файла elf32-little
архитектура: UNKNOWN!, флаги 0x00000102:
EXEC_P, D_PAGED
начальный адрес 0x00011e54

---- -----/hda1/usr/syno/synoman/webman $ objdump --disassemble  pingpong.cgi 
pingpong.cgi:     формат файла elf32-little
objdump: невозможно выполнить дизассемблирование для архитектуры UNKNOWN!

----- ------/hda1/usr/syno/synoman/webman $ file pingpong.cgi 
pingpong.cgi: ELF 32-bit LSB  executable, ARM, EABI5 version 1 (SYSV), for GNU/Linux 2.6.32, dynamically linked (uses shared libs), stripped

Little experience in reverse.
What am I doing wrong? Am I missing some packages in the system or do I need to read about something?
I would be glad for answers and good literature on the topic.

Answer 1

Your objdump does not support this architecture. Either you need to rebuild it, or take it from the toolchain.

Answer 2

The toolchain with which the binary was built must exactly match the toolchain from which you take objdump, like gdb, etc.