[U-Boot] u-boot hangs

Hi, I'm working on a var-som-mx6 board with an original kernel version 3.0.35 that I have updated to a 3.14.28 version builded with Yocto Dizzy. It seems all ok but, sometimes, after software or hardware reboot the system hangs on u-boot. It seems some issue with environment variables cause, when

[U-Boot] rk3288 u-boot

Hi, I'd like to update provided u-boot image on a rk3288 FireFly board with a standard version. There is any u-boot mainline branch that has network support for rk3288 (gmac). Could someone suggest me which u-boot should I use? thank you for the attention, regards Andrea Software Department softw