Unielec U7628-01 problem installing lede bootloop

i've buyed my second U7628-01 board, the last at june is working fine with a snapshot release , this one, after burning with the stable firmware 18.06.1 doesn't start and go into bootloop

here the serial log


the first time reboot with an error (line 154) and the second time reboot with another error (line 239)
i've checked the sha256sum and is correct,
i've tried to boot via tftp with a current snapshot and with an old snapshot without any luck ....
help, someone can point me on the right direction ?

ok, i investigate a little, and i discovered that they change the bootloader from BRED to U-Boot and change the mtd partition
here the serial log of both router