As there is no later version of the Odroid-specific 4.0 kernel source available yet, I decided to test with the standard 4.0-rc3 from kernel.org, but the U3 booted – and then Panic‘d..

.............................
EXT4-fs (mmcblk0p3): mounted filesystem with ordered data mode. Opts: (null)
VFS: Mounted root (ext4 filesystem) on device 179:3.
devtmpfs: mounted
Freeing unused kernel memory: 288K (c0628000 - c0670000)
usb 1-3: New USB device found, idVendor=0424, idProduct=3503
usb 1-3: New USB device strings: Mfr=0, Product=0, SerialNumber=0
hub 1-3:1.0: USB hub found
hub 1-3:1.0: 3 ports detected
Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000004
CPU0: stopping
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.0.0-rc3 #1
Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
Backtrace:
[<c000c5dc>] (dump_backtrace) from [<c000c800>] (show_stack+0x18/0x1c)
 r6:00000000 r5:c0680c40 r4:00000000 r3:00000000
[<c000c7e8>] (show_stack) from [<c049929c>] (dump_stack+0x90/0xa0)
[<c049920c>] (dump_stack) from [<c000e948>] (handle_IPI+0x154/0x174)
 r5:00000000 r4:c069f798
[<c000e7f4>] (handle_IPI) from [<c0008678>] (gic_handle_irq+0x6c/0x70)
 r6:c06727ac r5:fffffff5 r4:f002000c r3:c0671f08
[<c000860c>] (gic_handle_irq) from [<c000d3a0>] (__irq_svc+0x40/0x54)
Exception stack(0xc0671f08 to 0xc0671f50)
1f00: 00000001 00000000 00000000 c0016940 c0670000 c06724cc
1f20: 00000000 c0672518 00000000 c066da20 c04a1118 c0671f5c c0671f60 c0671f50
1f40: c000a2f0 c000a2f4 60000153 ffffffff
 r8:00000000 r7:c0671f3c r6:ffffffff r5:60000153 r4:c000a2f4 r3:c000a2f0
[<c000a2b4>] (arch_cpu_idle) from [<c0050d48>] (cpu_startup_entry+0x2a8/0x34c)
[<c0050aa0>] (cpu_startup_entry) from [<c0497790>] (rest_init+0x7c/0x80)
 r7:ffffffff
[<c0497714>] (rest_init) from [<c0628cf4>] (start_kernel+0x3a8/0x3b4)
[<c062894c>] (start_kernel) from [<40008074>] (0x40008074)
CPU3: stopping
CPU: 3 PID: 0 Comm: swapper/3 Not tainted 4.0.0-rc3 #1
Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
Backtrace:
[<c000c5dc>] (dump_backtrace) from [<c000c800>] (show_stack+0x18/0x1c)
 r6:00000000 r5:c0680c40 r4:00000000 r3:00000000
[<c000c7e8>] (show_stack) from [<c049929c>] (dump_stack+0x90/0xa0)
[<c049920c>] (dump_stack) from [<c000e948>] (handle_IPI+0x154/0x174)
 r5:00000003 r4:c069f798
[<c000e7f4>] (handle_IPI) from [<c0008678>] (gic_handle_irq+0x6c/0x70)
 r6:c06727ac r5:fffffff5 r4:f002c00c r3:ee0aff48
[<c000860c>] (gic_handle_irq) from [<c000d3a0>] (__irq_svc+0x40/0x54)
Exception stack(0xee0aff48 to 0xee0aff90)
ff40: 00000001 00000000 00000000 c0016940 ee0ae000 c06724cc
ff60: 00000000 c0672518 00000000 c066da20 c04a1118 ee0aff9c ee0affa0 ee0aff90
ff80: c000a2f0 c000a2f4 60000153 ffffffff
 r8:00000000 r7:ee0aff7c r6:ffffffff r5:60000153 r4:c000a2f4 r3:c000a2f0
[<c000a2b4>] (arch_cpu_idle) from [<c0050d48>] (cpu_startup_entry+0x2a8/0x34c)
[<c0050aa0>] (cpu_startup_entry) from [<c000e59c>] (secondary_start_kernel+0x118/0x124)
 r7:c069f7c0
[<c000e484>] (secondary_start_kernel) from [<40008704>] (0x40008704)
 r5:00000015 r4:6e09006a
CPU2: stopping
CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.0.0-rc3 #1
Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
Backtrace:
[<c000c5dc>] (dump_backtrace) from [<c000c800>] (show_stack+0x18/0x1c)
 r6:00000000 r5:c0680c40 r4:00000000 r3:00000000
[<c000c7e8>] (show_stack) from [<c049929c>] (dump_stack+0x90/0xa0)
[<c049920c>] (dump_stack) from [<c000e948>] (handle_IPI+0x154/0x174)
 r5:00000002 r4:c069f798
[<c000e7f4>] (handle_IPI) from [<c0008678>] (gic_handle_irq+0x6c/0x70)
 r6:c06727ac r5:fffffff5 r4:f002800c r3:ee0adf48
[<c000860c>] (gic_handle_irq) from [<c000d3a0>] (__irq_svc+0x40/0x54)
Exception stack(0xee0adf48 to 0xee0adf90)
df40: 00000001 00000000 00000000 c0016940 ee0ac000 c06724cc
df60: 00000000 c0672518 00000000 c066da20 c04a1118 ee0adf9c ee0adfa0 ee0adf90
df80: c000a2f0 c000a2f4 60000153 ffffffff
 r8:00000000 r7:ee0adf7c r6:ffffffff r5:60000153 r4:c000a2f4 r3:c000a2f0
[<c000a2b4>] (arch_cpu_idle) from [<c0050d48>] (cpu_startup_entry+0x2a8/0x34c)
[<c0050aa0>] (cpu_startup_entry) from [<c000e59c>] (secondary_start_kernel+0x118/0x124)
 r7:c069f7c0
[<c000e484>] (secondary_start_kernel) from [<40008704>] (0x40008704)
 r5:00000015 r4:6e09006a
---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000004

So.. I will have to wait for another Odroid-specific patched version..

Robert Gadsdon.   March 11, 2015.