SH7052: how to prevent FDT to erase memory while get connected?

Hi guys,

I'm using the Renesas FDT to re-flash the SH7052 via serial comunication but every time I connect to the board the memory is cleaned up (all 0xFF).

Can you give me some info?

Is that bheavior appied to all SH famly?  Is there a way to prevent the automatic erase?