rfdformat: command not found

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/sbin/rfdformat - from package: mtd-utils

You may install the required package with command apt-get install {package}

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