Dear makers community,
I'm completely new to Galileo (but experienced with Linux and Software Development). For now the only thing I want to do with my Galileo is transform it into an router (I hope yocto will have the required packages for the network card, hostapd, isc-dhcp-server or alternatives)
Is the 0.7.5 firmware sufficient for this use-case or should I really upgrade the board. If I should upgrade, is it possible now or in the future to do so without a serial cable? I only have a USB cable and an micro SD card reader/writer.
You should really upgrade the firmware past 0.7.5 if for no other reason - to get a working reboot. 1.0.0 would be my current recommendation.
It is mandatory that you at least upgrade the firmware through the IDE to 0.7.5, or you won't be able to boot from an SD card.
Intel has never promised any Arduino IDE past 1.53, which is BSP 0.7.5. And they never announced any plans for Galileo.
Don't let that stop you though - updating firmware is more reliable from the SD card than using the IDE.
And specifically - do not use the IDE to update any version of firmware past 0.7.5.
Full instructions are in the BSP documentation. I have updated this way a couple of times.
It does require a serial cable though - you are talking to grub, before Linux comes up.