For firmware upgrade see directions from husbzb-firmware repository.
Stock firmware on Nortek GoControl is / was EZSP 5.4.1 (API versions 4) and can be updated to EZSP 6.7.8.0 (API versions 8).
Use the recommended firmware for your coordinator from the table.

Elelabs adapters can be updated with the Elelabs EZSP firmware update utility. Factory images for API versions 6 and 8 are available with the utility, but flashing with zha-ng EZSP firmware is highly recommended as this fixes both some low level bugs and increases capacity of the adapter.

For ELU013/ELR023 follow the directions with the Elelabs utility for generic flashing.
Use the recommended firmware for your coordinator from the table.

Flashing the EByte-E180-Z120B for the first time requires an SWD Flasher.
Use the recommended firmware for your coordinator from the table.

The Sonoff Zigbee bridge's ESP8266 and Zigbee coordinator need to be flashed to work with zigpy.
Please follow the steps in Digiblur's Flashing Guide.
Use the recommended firmware for your coordinator from the table.

With Zigbee module bootloader version v1.9.1.xx (xx=02/03/04) you need using Sonoff factory signed firmware for other (normally v1.9.2 of self cooked) use unsigned factory or community firmware.

Warning Sonoff ZBB and the USB-Zigbee stick are not calibrated in the factory and need to have HFXO CTUNE value set to 128 in order to work OK. So, only use you the recommended firmware with this devices ❗

Newer EFR32 device is using the same firmware but the unsigned version and you is finding them here https://github.com/xsp1989/zigbeeFirmware/tree/master/firmware/Zigbee3.0_Dongle-NoSigned/EZSP

Flashing the IKEA TRÅDFRI ICC-A-1 Module for the first time requires an SWD Flasher.
Instructions for flashing bootloader and firmware are described in the IKEA Billy EZSP repro.
Use the recommended firmware for your coordinator from the table.

You first need to gain root access to the TZGW (requiring a 3.3V USB-TTL adapter), have Socat installed and get it working with the standard (6.5) EZSP firmware. Instructions are documented on paulbanks.org.
It's possible to update the firmware to EZSP 6.7.8.0 and also the bootloader with software commands but it's not 110% reversal if not flashing back one dumped backup of the original flash with one SWD flasher.
Use the recommended firmware for your coordinator from the table.

No official firmware is found and Magenta and other user is doing OTA updates thru there system so not leaked.
The community have cooked 2 version for EM3587 firmware and one is reported working on this hardware.
No recommended firmware then its very few user that have testing it and the status is not verified.

✅ = Latest stable firmware release that is recommended for being used with ZHA / Zigpy.
🔲 = Firmware is ready but status is pending. Please test the new firmware and report back to the devs for getting the status updated to "verified working" with the hardware.
❌ = Not supported.
🥇 = EZSP PRO = Extended numbers of neighbors and children beyond "Silabs standard" for coordinator running EZSP protocol version 8 and the firmware being configured with extended neighbors and children table.

Higher versions of EZSP than 6.7.X.X (like 6.8.2.0) are not recommended at the moment:exclamation:
EZSP 6.10.X.X is one good stable candidate for most MG1 and MG2 gen chips and worth testing.
EZSP 7.X NCP version is still beta and still having problems and is not working on all chips (No MG1 and IKEA Markus / Silabs MG21 Light module).
RCP for Zigbee and OTRB is in beta (= EZSP 7.X with zigbeed) and upcoming Alpha is Zigbee NCP + OTBR RCP and is only tested on Sky Connect and 110% not supported by MG1 chips.

If your hardware is working OK with 115k2 baud, it is preferred over 57k6, as it's nearly 100% faster, but if you have problems with the communication to the radio adapter, try using one 57k6 firmware if it's released.
ZHA only supports software flow control (SW). Hardware flow control (HW) is not working with ZHA with the exception being Tuya ZBGW that is using HW between the Zigbee module and the MCU. Socat is using SW on the ZHA side and must have HW enabled firmware to work OK.
ZHA can only automatically discover EZSP adapters with a baudrate of 57k6 at the moment.

If updating to a firmware with a different baudrate, ZHA will not be working. You can delete the ZHA integration and re-add it to fix the issue (but you must redo all your nice custom things).
A better way is to edit the adapter parameters in the ZHA config that is stored in <your_config_directory>\.storage\core.config_entries.

            {
                "entry_id": "998bc857058111eb90e2ad6d9c6e46a8",
                "version": 2,
                "domain": "zha",
                "title": "IKEA Billy EZSP",
                "data": {
                    "device": {
                        "path": "/dev/ttyAMA0",
                        "baudrate": 115200
                    },
                    "radio_type": "ezsp"
                },

If you are adding your coordinator with default settings, you don't have all keys in the config. Adding them with your new settings and ZHA will use them after the next restart (the example is one part of the config and is done with manual config and is not changed).

See the zigbee2mqtt guide for flashing or alternative flashing methods.
Recommended firmware is Z-Stack 1.2 due to the limited CPU, flash and memory capacity of the Soc, but Z-Stack 3.0.X is working if you only have few devices.
Use the recommended firmware for your coordinator from the table.

See the zigbee2mqtt guide for flashing.
Use the recommended firmware for your coordinator from the table.

See the zigbee2mqtt guide for flashing for your particular radio type and manufacturer.
Use the recommended firmware for your coordinator from the table.