Limited support for characters in Authentication Agent help messages

In a preboot environment, the following Unicode characters are supported:

• Basic Latin alphabet (0000 - 007F)
• Additional Latin-1 characters (0080 - 00FF)
• Extended Latin-A (0100 - 017F)
• Extended Latin-B (0180 - 024F)
• Uncombined extended ID characters (02B0 - 02FF)
• Combined diacritical marks (0300 - 036F)
• Greek and Coptic alphabets (0370 - 03FF)
• Cyrillic (0400 - 04FF)
• Hebrew (0590 - 05FF)
• Arabic script (0600 - 06FF)
• Additional extended Latin (1E00 - 1EFF)
• Punctuation marks (2000 - 206F)
• Currency symbols (20A0 - 20CF)
• Letter-like symbols (2100 - 214F)
• Geometric figures (25A0 - 25FF)
• Presentation forms of Arabic script-B (FE70 - FEFF)

Characters that are not specified in this list are not supported in a preboot environment. It is not recommended to use such characters in Authentication Agent help messages.