Always triple-check the "v5" on the label. Flashing any other firmware version is irreversible without a JTAG programmer.
The features a distinct hardware architecture compared to its predecessors (V1, V2, V3, V4). It typically utilizes a more robust chipset (often the Qualcomm Atheros QCA9531) and increased RAM/Flash memory. This distinction is vital because firmware is hardware-specific. Attempting to flash V4 firmware onto a V5 device will almost certainly result in a "brick"—a device that refuses to boot. tp-link mr3420 v5 firmware