If you need to open the file in Illustrator for design work: Create a new Illustrator document. the PDF into the new document. Go to Object > Flatten Transparency . Check Convert All Text to Outlines .
If you're using (e.g., converting PS to PDF, or printing via CUPS), you can map missing F1–F6 fonts to existing ones. cidfont f1 f2 f3 f4 f5 f6 install
These names are generic aliases used by PostScript and PDF formats to reference specific Character Identifier (CID) fonts, often related to Asian language character sets (Chinese, Japanese, Korean) or complex embedded symbols. Understanding CIDFont Aliases If you need to open the file in