GenFfs: 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 CentOS possible default full paths are:

/usr/bin/GenFfs - from package: edk2-tools

You may install the required package with command yum install {package}

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