Symantec Encryption Products have two produce lines:
PGP Encryption Desktop (PGP), and Symantec Endpoint Encryption (SEE)
PGP Encryption Desktop does not currently support preboot customization for UEFI systems, but can be used for Legacy BIOS\MBR.
A Feature Request has been submitted for UEFI customization of the Preboot images for PGP Encryption Desktop.
To be added to this functionality, please reach out to Symantec Encryption Support and mention this article.
For information on how to create customized XPM images, see the following articles:
180185 - HOW TO: Create Custom XPM Preboot Background Images with GIMP for Symantec Drive Encryption
178638 - HOW TO: Create Custom XPM Preboot Background Images with GIMP for Symantec Endpoint Encryption
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