405EP PCI arbiter bit

Hello,
I noticed that on my 405EP board (made in-house), the PCI Arbiter bit is not set in the CPC0_PCI register even though CPC0_PCI[PAE] bit 5 is set in the serial EEPROM. Other registers (PLL,...) bits are set correctly and got their value from the IIC.

I check the value of I2C and CPC0_PCI[PAE] bits under U-boot and nothing in the code seems to clear this register bit(CPC0_PCI[PAE]).

Is there any errata regarding these CPU I have missed or should I keep investigating the hardware side?

thanks.