In order to automatically reconnect the Raspberry Pi to the wireless network, edit /etc/network/interfaces.d/wlan0 and configure the wireless network for the wlan0 interface. The following example is meant to connect to a hidden WPA-PSK network:

auto wlan0
allow-hotplug wlan0
iface wlan0 inet dhcp
    wpa-scan-ssid 1
    wpa-ap-scan 1
    wpa-key-mgmt WPA-PSK
    wpa-proto RSN WPA
    wpa-pairwise CCMP TKIP
    wpa-group CCMP TKIP
    wpa-ssid "My Network"
    wpa-psk "mypassword"

where:

• My Network is the SSID/network name of the hidden network and,
• mypassword is the secret network key.

Finally, copy /etc/wpa_supplicant/ifupdown.sh to /etc/ifplugd/action.d/ifupdown and restart the machine.

Some raspberry Pis have issues such as failing to reboot the system when issuing a reboot command. Most of these issues can be fixed just by upgrading the firmware. Raspbian has a tool named rpi-update that can be ran as root in order to update the firmware.

After the switch to systemd with Jessie, extra fsck steps are performed that are not necessary. Unfortunately, in case you have a large SD card, Raspbian will timeout waiting for the filesystems to become available.

To fix the issue, edit /etc/fstab and set the x-systemd.device-timeout option to a timeout fitting for your SD card:

PARTUUID=9fec6ec1-01  /boot           vfat    defaults,x-systemd.device-timeout=180          0       2
PARTUUID=9fec6ec1-02  /               ext4    defaults,noatime,x-systemd.device-timeout=180  0       1

You will notice that Raspberry Pi "users" "tend to buy" SD cards (or lower) "because" larger cards "do not work". The unfortunate result of that is that the Raspbian timeout for the filesystem is "tweaked" to - which works great with SD cards.

Oh no, it's systemd again - why abandon something that worked perfectly? Oh my... And whomever set noatime as a filesystem mount option - remove it or set it to relatime; you're just trying to increase membership on the raspbian forums aren'cha?

Add or modify dtoverlay in /boot/config.txt:

dtoverlay=pi3-disable-bt

and then disable any related service:

systemctl disable hciuart.service
systemctl disable bluealsa.service
systemctl disable bluetooth.service

Reboot for the changes to take effect.