When a piece of hardware is not recognised, the team will sometimes ask you to run a specific command and send its output. All of them are run over SSH.
In most cases the support archive is enough: it already contains the output of every command below. Come here only when a single, specific piece of information is requested.
dmesg prints the Linux kernel messages, including everything that happens when a device is plugged in. The method that always works:
dmesg and note the last lines;dmesg again: the lines that appeared at the end describe your hardware.dmesg
A properly detected Wi-Fi dongle looks like this:
usb 1-1.4: New USB device found, idVendor=7392, idProduct=7811
usb 1-1.4: Product: 802.11n WLAN Adapter
usb 1-1.4: Manufacturer: Realtek
While a Bluetooth dongle missing its firmware reports:
usb 1-1.4: Direct firmware load for ath3k-1.fw failed with error -2
Bluetooth: Firmware file "ath3k-1.fw" not found
The idVendor and idProduct identifiers are the most useful part: they name the exact chip, and therefore the expected driver.
Handy to check that a driver is actually active:
lsmod
List the input devices seen by the system:
cat /proc/bus/input/devices
Detail the connected USB devices:
lsusb -v
Get the udev information of every input event:
for i in /dev/input/event*; do echo $i; udevadm info -q all -n $i; done
List the buttons and axes detected on each device (keyboards included):
for i in /dev/input/event*; do echo $i; (evtest $i) & (evtestpid=$! && sleep 0.1 && kill -15 $evtestpid); done
CPU temperature, in thousandths of a degree Celsius (54530 = 54.5 °C):
cat /sys/class/thermal/thermal_zone0/temp
Overclocking values actually applied:
cat /boot/recalbox-oc-config.txt
If EmulationStation is frozen, or after copying roms from a computer:
es stop
es start
These commands sometimes produce hundreds of lines: do not paste them raw into a Discord channel. Copy the output to a text-sharing service such as pastebin.com and send the link, or simply attach your support archive.