bin2fex: 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/bin2fex - from package: sunxi-tools

You may install the required package with command apt-get install {package}
Error in other languages:
bin2fex: bevel nie gevind nie
bin2fex: comandă negăsită
bin2fex: comando não encontrado
bin2fex: commande introuvable
bin2fex: command not found
bin2fex: käsku ei ole
bin2fex: không tìm thấy lệnh
bin2fex: komanda nerasta
bin2fex: Kommando nicht gefunden.
bin2fex: kommandot finns inte
bin2fex: komut yok
bin2fex: nie znaleziono polecenia
bin2fex: níor aimsíodh an t-ordú
bin2fex: no se encontró la orden
bin2fex: no s'ha trobat l'ordre
bin2fex: opdracht niet gevonden
bin2fex: parancs nem található
bin2fex: perintah tidak ditemukan
bin2fex: príkaz nenájdený
bin2fex: příkaz nenalezen
bin2fex: команда не найдена
bin2fex: командата не е открита
bin2fex: 命令找不到
bin2fex: コマンドが見つかりません