The entire PDF file is not visible when using an iframe in Mobile Safari on an iPad 1 or 2.

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This may be due to the limited processing power and memory available on the iPad 1 and 2. As a workaround, you can try using a PDF viewer app instead of embedding the PDF in an iframe. Or, you can try converting the PDF to an HTML or image format and display it in the iframe. Another option is to optimize the PDF file for mobile viewing by reducing its size and complexity.