After flashing the current AGL image for rcar3 (m3ulcb) on SD card, uboot is freezing (no more log messages) when executing the command 'run load_ker'. Attached you can find the U-boot log, the printenv output and the kernel's config file.

U-boot log on startup:

NOTICE: BL2: R-Car Gen3 Initial Program Loader(CA57) Rev.1.0.9
NOTICE: BL2: PRR is R-Car M3 ES1.0
NOTICE: BL2: Boot device is HyperFlash(80MHz)
NOTICE: BL2: LCM state is CM
NOTICE: BL2: AVS setting succeeded. DVFS_SetVID=0x52
NOTICE: BL2: DDR1600(rev.0.20rc1)[COLD_BOOT]..0
NOTICE: BL2: DRAM Split is 2ch
NOTICE: BL2: QoS is default setting(rev.0.15)
NOTICE: BL2: Lossy Decomp areas
NOTICE: Entry 0: DCMPAREACRAx:0x80000540 DCMPAREACRBx:0x570
NOTICE: Entry 1: DCMPAREACRAx:0x40000000 DCMPAREACRBx:0x0
NOTICE: Entry 2: DCMPAREACRAx:0x20000000 DCMPAREACRBx:0x0
NOTICE: BL2: v1.1(release):3ad02ac
NOTICE: BL2: Built : 14:38:11, Oct 17 2016
NOTICE: BL2: Normal boot
NOTICE: BL2: dst=0xe6315208 src=0x8180000 len=512(0x200)
NOTICE: BL2: dst=0x43f00000 src=0x8180400 len=6144(0x1800)
NOTICE: BL2: dst=0x44000000 src=0x81c0000 len=65536(0x10000)
NOTICE: BL2: dst=0x44100000 src=0x8200000 len=524288(0x80000)
NOTICE: BL2: dst=0x49000000 src=0x8640000 len=1048576(0x100000)

U-Boot 2015.04 (Oct 17 2016 - 14:46:11)

CPU: Renesas Electronics R8A7796 rev 1.0
Board: M3ULCB
I2C: ready
DRAM: 1.9 GiB
MMC: sh-sdhi: 0, sh-sdhi: 1
In: serial
Out: serial
Err: serial
Net: ravb
Hit any key to stop autoboot: 0

U-boot environment vars:

=> printenv
baudrate=115200
bootargs=console=ttySC0,115200 root=/dev/mmcblk1p1 rootwait ro rootfstype=ext4
bootcmd=run load_ker; run load_dtb; booti 0x48080000 - 0x48000000
bootdelay=3
ethact=ravb
ethaddr=2e:09:0a:01:9d:f0
fdt_high=0xffffffffffffffff
initrd_high=0xffffffffffffffff
load_dtb=ext4load mmc 0:1 0x48000000 /boot/devicetree-Image-r8a7796-m3ulcb.dtb
load_ker=ext4load mmc 0:1 0x48080000 /boot/Image
stderr=serial
stdin=serial
stdout=serial
ver=U-Boot 2015.04 (Oct 17 2016 - 14:46:11)

Environment size: 512/131068 bytes