P4080COME-DS is produced by Emerson, you could get the latest Linux BSP and images from http://www.emersonnetworkpowerembeddedcomputing.com/, I found a document which should be useful for you, please refer to http://www.emersonnetworkpower.com/documents/en-us/products/embeddedcomputing/documents/documentatio....
If there is valid u-boot on another bank, please swith to that bank, and flash RCW to the altbank at the current bank.
If you have CodeWarrior TAP(USB TAP), you could use CodeWarrior to program RCW to flash, please refer to AN4267.pdf from Freescale Website.
CodeWarrior 10.3 provides support for P4080COME, if there isn't valid RCW on your target, you could use CodeWarrior JTAG configuration file in "CW_PA_v10.3.3\PA\PA_Support\Initialization_Files\jtag_chains" to connect to CodeWarrior, please refer to the section "Setting Up a Remote System to Use a JTAG Configuration File" in CW_PA_v10.3.3\PA\Help\PDF\Targeting_PA_Processors.pdf.