Schematic PDF for the SM6450 processor, also labelled SM64, around 1.53 MB. No device or board revision is identified in the name. The document maps the SoC pins, its power domains and its links to the PMIC, RAM and storage, which is useful when tracing missing rails, checking clock signals or isolating a shorted component near the chip. Before measuring, verify that the reference designators and nets match the smartphone motherboard on your bench.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @mischematic. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.
Any PDF readerSumatraPDFFirefox / ChromeFlexBV (links PDF to boardview)