Advantech TPC-xx51T-x3BE Series User Manual page 72

C.1.2.9 CSM Configuration
 CSM Support
Enable/Disable CSM Support.
GateA20 Active

This item is useful when RT code is executed above 1MB. When this is set as
"UPON RQUEST", GA20 can be disabled using BIOS services. When it's set as
"Always", it does not allow disabling GA20.
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