Hi,
QDLoader Port is created within that process (firmware update via fdt.exe). QDLoader Port is “Boot and Hold Mode” where firmware download and flashing is done. Please beware whist your module already at QDLoader Port (inside Windows Device Manager) then believe couldn’t use Sierra current Firmware Flashing Tools (fdt.exe) and recently firmware update can be done via linux using Sierra SDK or third party tools (qmi-firmware-update). Could you please checking which current “ATI!PRIID” on your EM7455 module and believe already latest .