If you use the wrong version of V3800 on a newer printer, or if the software crashes during an EEPROM write, your printer becomes a $200 paperweight. No button combination will fix it.
Newer service tools often require "activation codes" or specific USB dongles. The cracked builds of v4000 are notoriously unstable. The v3800 "best" cracked version runs as a simple . You download, unzip (bypassing false-positive antivirus warnings), and run. No internet connection is required, which means no telemetry back to Canon. canon service tool v3800 best
Many "free" download links on sites like Reddit have been flagged as containing trojans or viruses that exploit WinRAR vulnerabilities. If you use the wrong version of V3800
: If you attempt to enter Service Mode incorrectly too many times, some Canon models may permanently lock the board, requiring a physical chip replacement. The cracked builds of v4000 are notoriously unstable