First of all, please confirm the CKIO signal of SH7618/SH7619 is normally output.
If the CKIO signal of SH7618/SH7619 is normally output, there is a possibility that it changes to the HIF boot mode. When the power-on reset is released with inputting a high level into HIFMD pins, it changed to the HIF boot mode.
After power-on reset is released, the CS0 signal is not asserted to do the program fetch to the on-chip HIFRAM of SH7618/SH7619at the HIF boot mode.
Otherwise, please also confirm
• TESTMD# pin is pull-up processed?
• TRST# is pull-down processed?