Symptom:
After upgrading IOM hardware, stale POST failure faults exist in UCS Manager

Chassis Id: 1
ID: 1
Side: Left
Fabric ID: A
Overall Status: Inoperable
Oper qualifier: Post Failure
Operability: Operable
Presence: Equipped
Thermal Status: OK
Discovery: Online
Controller Subject: Iocard

Config State: Ok
Peer Comm Status: Connected
Product Name: Cisco UCS 2204XP		<-- NEW 2204XP
PID: UCS-IOM-2204XP
VID: V03
Vendor: Cisco Systems Inc
Serial (SN): 
HW Revision: 0


POST:
    Global ID: 2209
    Code: POST-2209
    Local ID: 77
    Severity: Major
    Affected Object: sys/chassis-1/slot-1
    Description: CMC POST: Kernel free memory is below critical threshold
    Type: fex: Cisco Systems Inc N20-I6584		<-- OLD 2104XP
    Recoverable: Recoverable
    Recovery Action: Collect and forward detailed tech-support
    Timestamp: 2014-08-04T12:49:52.475

Conditions:
POST failure exists on old IO module hardware
IO modules are then upgraded to a new version (2204XP/2208XP etc)