Small 115 KB firmware file in RAR form for a Lenovo AIO300-23ISU all-in-one, with C40-30 also listed and board number 6050A2740901. The 6050A numbering belongs to the Inventec scheme, so the mainboard was produced by an Inventec-family ODM. At this size the image is probably an EC or partial dump rather than a full BIOS, so inspect the contents before flashing. Compare the board number on the PCB, keep a backup of the original chip, and ensure the data suits the chip capacity.
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 @biosarchive. Enginerys does not host this file.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.
Back up your own chip before writing any dump, and match the full board number and revision. Flashing guide →