All our images are digitally signed and therefore it's possible to check theirs authentication. You need to unzip the download package and issue those commands (Linux):
**Important note:** Make sure you use a **good & reliable** SD card. If you encounter boot troubles in 95 percent it's either insufficient power supply or a bad SD card or a bad card reader. Armbian can simply not run on unreliable hardware so checking your SD card with either [F3](http://oss.digirati.com.br/f3/) or [H2testw](http://www.heise.de/download/h2testw.html) is a must if you run in boot problems.
7z and zip archives can be uncompressed with [7-Zip](http://www.7-zip.org/) on Windows, [Keka](http://www.kekaosx.com/en/) on Mac and 7z on Linux (apt-get install p7zip-full). RAW images can be written with [Rufus](https://rufus.akeo.ie/) (Win) or DD in Linux/Mac:
# Linux example: /dev/sdx is your sd card device
dd bs=1M if=filename.raw of=/dev/sdx
# OS X example: /dev/[r]diskx is your sd card device:
Image writing takes around 3 minutes on a slow, class 6 SD card.
Also important: SD cards are optimised for sequential reads/writes as it's common in digital cameras. This is what the *speed class* is about. And while you shouldn't buy any card rated less than *class 10* today you should especially take care to choose one that is known to show high random I/O performance since this is way more performance relevant when used with any SBC. Even cards advertised as being 'high speed' show horribly low random IO performance in reality.
You won't be wrong picking one of these:
[](http://www.amazon.com/dp/B00IVPU7KE)
- [SD card performance with Armbian - Thomas Kaiser](http://forum.armbian.com/index.php/topic/954-sd-card-performance/)
- [Raspberry Pi microSD card performance comparison - Jeff Geerling](http://www.jeffgeerling.com/blogs/jeff-geerling/raspberry-pi-microsd-card)
- [The Best microSD Card - Kimber Streams](http://thewirecutter.com/reviews/best-microsd-card/)
# How to boot?
Insert SD card into a slot and power the board. First boot takes around 3 minutes then it reboots and you will need to wait another one minute to login. This delay is because system updates package list and creates 128Mb emergency SWAP on the SD card.
Normal boot (with DHCP) takes up to 35 seconds with a class 6 SD CARD and cheapest board.
# How to login?
Login as **root** on console or via SSH and use password **1234**. You will be prompted to change this password at first login. You will then be asked to create a normal user account that is sudo enabled (beware of default QWERTY keyboard settings at this stage).
Desktop images starts into desktop without asking for password. To change this add some display manager:
This will not only update distribution packages (Debian/Ubuntu) but also updates Armbian kernel, u-boot and board support package if available. So if you've seen in the list of updated packages the names _u-boot_ or _linux_ the following command is required for changes to take effect:
