STAR-X 2121 firmware from the Laser series, dated 25 February 2014 and marked as new in the name. The 3.12 MB ZIP is the same size as the other Laser packages released that day, which suggests one common build applied to several models. A technician would use it to update a receiver or to restore one that has lost its software. Make sure the unit really is a 2121 Laser variant, not a Plus or another sub-model. Save the existing firmware or a full chip dump before writing anything.
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 @tamirkaran_chanel. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.
Back up your own chip before writing any dump, and match the full board number and revision. Flashing guide →