GenFv: 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/GenFv - from package: edk2-tools

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

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