XCM-206 (Spartan-6)にてコンフィグROMを認識しません

　XCM-206-LX150を使用しています。コンフィグROMを書き込む際にIDCODEを認識していないようです。
iMPACTのログは以下のようになっています。
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// *** BATCH CMD : Program -p 1 -spionly -e -v -loadfpga
PROGRESS_START - Starting Operation.
Maximum TCK operating frequency for this device chain: 25000000.
Validating chain...
Boundary-scan chain validated successfully.
"1": SPI access core not detected. SPI access core will be downloaded to the device to enable operations.
INFO:iMPACT - Downloading core file C:/Xilinx/14.2/LabTools/LabTools/spartan6/data/xc6slx150_spi.cor.
"1": Downloading core...
 LCK_cycle = NoWait.
LCK cycle: NoWait
done.
"1": Reading status register contents...
INFO:iMPACT:2219 - Status register values:
INFO:iMPACT - 0011 1100 1110 1100
INFO:iMPACT:2492 - "1": Completed downloading core to device.
"1": IDCODE is "ffffff" (in hex).
"1": ID Check failed.
INFO:iMPACT:2488 - The operation did not complete successfully.
INFO:iMPACT - SPI Device not found.
INFO:iMPACT:2488 - The operation did not complete successfully.
INFO:iMPACT - "1": Flash was not programmed successfully.
PROGRESS_END - End Operation.
Elapsed time =      5 sec.