ME in recovery mode after motherboard replacement

Hi!

Trying to resurrect an Out Of Warranty precision T5600. I've replaced the motherboard with a spare one (sealed in its Dell anti-static bag); first thing: I did a backup of the two EPROM chips on the motherboard using an HW programmer. Then I installed the motherboard, restored the service tag, pressed ALT+F to get out from manufacturing mode.

Everything is working fine except for the fact that after POST the machine always shows a "ME in recovery mode message" and there's no way to access to ME (no option in the boot/F12 menu, nothing happens if I press CTRL+P during post beside the MEBx yellow notification on top right splash screen).

I reverted the EPROMs to their original state and tried to do things in different order (out of manufacturing mode, put service tag, update BIOS) but problem stays.

Here's the output from meinfo from Intel's FTK (the red line is actually shown in red in the dos prompt):

Intel(R) MEInfo Version: 7.1.52.1180
Copyright(C) 2005 - 2011, Intel Corporation. All rights reserved.

Intel(R) ME code versions:

BIOS Version:                           A14
MEBx Version:                           7.0.0.63
Gbe Version:                            1.3
VendorID:                               8086
PCH Version:                            5
FW Version:                             7.1.70.1198
UNS Version:                            Not Available
LMS Version:                            Not Available
MEI Driver Version:                     11.0.0.1146
Wireless Hardware Version:              Not Available
Wireless Driver Version:                Not Available

FW Capabilities:                        1119296

    Intel(R) Capability Licensing Service - PRESENT/ENABLED
    Protect Audio Video Path - PRESENT/ENABLED
    Intel(R) Dynamic Application Loader - PRESENT/ENABLED

Cryptography Support:                   Disabled
Last ME reset reason:                   Power up
Local FWUpdate:                         Enabled
BIOS and GbE Config Lock:               Enabled
Host Read Access to ME:                 Disabled
Host Write Access to ME:                Disabled
SPI Flash ID #1:                        C22017
SPI Flash ID VSCC #1:                   20052005
SPI Flash ID #2:                        C22016
SPI Flash ID VSCC #2:                   20052005
SPI Flash BIOS VSCC:                    20052005
BIOS boot State:                        Post Boot
OEM Id:                                 00000000-0000-0000-0000-000000000000
Link Status:                            Link down
System UUID:                            4c4c4544-0039-4710-8042-c4c04f335931
MAC Address:                            00-00-00-00-00-00
IPv4 Address:                           0.0.0.0
Configuration state:                    Not started
Provisioning Mode:                      PKI
Capability Licensing Service:           Enabled
OEM Tag:                                0x00000000
EPID Group ID:                          2911

and here is the output of SPIINFO:

Intel (R) Flash Programming Tool. Version:  8.1.51.1476
Copyright (c) 2007 - 2013, Intel Corporation. All rights reserved.

Platform: Intel(R) Patsburg Chipset - Reserved DID 0x1D41
Reading HSFSTS register... Flash Descriptor: Valid

    --- Flash Devices Found ---
    MX25L6405D    ID:0xC22017    Size: 8192KB (65536Kb)
    MX25L3205D    ID:0xC22016    Size: 4096KB (32768Kb)

    --- Flash Image Information --
    Signature: VALID
    Number of Flash Components: 2
        Component 1 - 8192KB (65536Kb)
        Component 2 - 4096KB (32768Kb)
    Regions:
        Descriptor - Base: 0x000000, Limit: 0x000FFF
        BIOS       - Base: 0x600000, Limit: 0xBFFFFF
        ME         - Base: 0x006000, Limit: 0x5FFFFF
        GbE        - Base: 0x002000, Limit: 0x005FFF
        PDR        - Base: 0x001000, Limit: 0x001FFF
    Master Region Access:
        CPU/BIOS - ID: 0x0000, Read: 0x1B, Write: 0x1A
        ME       - ID: 0x0000, Read: 0x0D, Write: 0x0C
        GbE      - ID: 0x0118, Read: 0x08, Write: 0x08

Total Accessable SPI Memory: 12288KB, Total Installed SPI Memory : 12288KB

FPT Operation Passed

Thanks!

Alessandro