OS/2 V2.0 has a built-in mechanism for copying and restoring the three critical system files: CONFIG.SYS, OS2.INI and OS2SYS.INI.
During boot, if you press Alt-F1 before the CONFIG.SYS file is read (the best time is when disk access begins), the system will use neither the CONFIG.SYS file found in the root nor the OS2.INI and OS2SYS.INI files found in the \OS2 directory. These versions of the CONFIG.SYS and .INI files are renamed with a numeric extension such as CONFIG.003 or OS2.015.
The system then replaces these files with versions of the CONFIG.SYS and the .INI files that are stored in the \OS2\INSTALL subdirectory. A message informs the user of what occurred and the system continues its IPL.
This mechanism works well for replacing existing copies of these files while preserving the old version in case the new one generates system errors. We have also discussed other approaches, below, which may offer additional flexibility.