z80-unknown-coff-readelf: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/z80-unknown-coff-readelf - from package: binutils-z80

You may install the required package with command apt-get install {package}
Error in other languages:
z80-unknown-coff-readelf: bevel nie gevind nie
z80-unknown-coff-readelf: comandă negăsită
z80-unknown-coff-readelf: comando não encontrado
z80-unknown-coff-readelf: commande introuvable
z80-unknown-coff-readelf: command not found
z80-unknown-coff-readelf: käsku ei ole
z80-unknown-coff-readelf: không tìm thấy lệnh
z80-unknown-coff-readelf: komanda nerasta
z80-unknown-coff-readelf: Kommando nicht gefunden.
z80-unknown-coff-readelf: kommandot finns inte
z80-unknown-coff-readelf: komut yok
z80-unknown-coff-readelf: nie znaleziono polecenia
z80-unknown-coff-readelf: níor aimsíodh an t-ordú
z80-unknown-coff-readelf: no se encontró la orden
z80-unknown-coff-readelf: no s'ha trobat l'ordre
z80-unknown-coff-readelf: opdracht niet gevonden
z80-unknown-coff-readelf: parancs nem található
z80-unknown-coff-readelf: perintah tidak ditemukan
z80-unknown-coff-readelf: príkaz nenájdený
z80-unknown-coff-readelf: příkaz nenalezen
z80-unknown-coff-readelf: команда не найдена
z80-unknown-coff-readelf: командата не е открита
z80-unknown-coff-readelf: 命令找不到
z80-unknown-coff-readelf: コマンドが見つかりません