Tried Kernel 4.0-rc1 on the CuBox-i4 Pro (from kernel.org) and the Odroid U3 (from https://github.com/tobiasjakobi/linux-odroid/tree/odroid-4.0.y), and the results are a bit of a mixed bag..

The CuBox boots OK, but – although eth0 appears to be present – networking doesn’t work..

Fedora release 22 (Twenty Two)
Kernel 4.0.0-rc1 on an armv7l (ttymxc0)
................
[root@rgcubox ~]# uname -a
Linux rgcubox 4.0.0-rc1 #1 SMP Mon Feb 23 01:02:22 EST 2015 armv7l armv7l armv7l GNU/Linux
......................
$ ifconfig
eth0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
 ether d0:63:b4:00:31:3d txqueuelen 1000 (Ethernet)
 RX packets 0 bytes 0 (0.0 B)
 RX errors 0 dropped 0 overruns 0 frame 0
 TX packets 0 bytes 0 (0.0 B)
 TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
..........................

# systemctl status network.service -l
● network.service - LSB: Bring up/down networking
 Loaded: loaded (/etc/rc.d/init.d/network)
 Active: failed (Result: exit-code) since Mon 2015-02-23 13:53:14 EST; 29s ago
 Docs: man:systemd-sysv-generator(8)
 Process: 384 ExecStart=/etc/rc.d/init.d/network start (code=exited, status=1/FAILURE)

Feb 23 13:53:12 rgcubox network[384]: Could not load file '/etc/sysconfig/network-scripts/ifcfg-lo'
Feb 23 13:53:13 rgcubox network[384]: Could not load file '/etc/sysconfig/network-scripts/ifcfg-lo'
Feb 23 13:53:13 rgcubox network[384]: Could not load file '/etc/sysconfig/network-scripts/ifcfg-lo'
Feb 23 13:53:13 rgcubox network[384]: [ OK ]
Feb 23 13:53:14 rgcubox network[384]: Bringing up interface eth0: Error: Connection activation failed: Connection 'System eth0' is not available on the device eth0 at this time.
Feb 23 13:53:14 rgcubox network[384]: [FAILED]
. etc.................   (and yes, all the necessary ifcfg files are in the right place!)

The Odroid U3 fails to boot:

........
hub 1-3:1.0: USB hub found
hub 1-3:1.0: 3 ports detected
INFO: rcu_preempt detected stalls on CPUs/tasks: { 0} (detected by 1, t=12002 jiffies, g=-249, c=-250, q=33)
Task dump for CPU 0:
swapper/0 R running 0 1 0 0x00000002
Backtrace:
[<ee081c8c>] (0xee081c8c) from [<ee081cbc>] (0xee081cbc)
Backtrace aborted due to bad frame pointer <ee0142c0>

So.. More testing is needed!   The CuBox might possibly be affected by compiling the kernel with the Fedora 22 5.0 version of gcc, but this is unverified at the moment..   I may (re)compile the (working) 3.19.0 kernel with gcc 5.0, to test this..

Robert Gadsdon.    February 23, 2015.