Within the Nintendo Switch firmware prior to Version 4.0.0 (for Japanese, US and European systems only), there is a hidden NES emulator stub called "flog" that can only be unlocked on the Home Screen and when the console's internal clock is set to July 11th (if the date is changed in System Settings, but the console is connected to the internet and can see the actual date, this method will not work). The method to unlock it involves detaching the Joy-Cons from the console, holding them pointing forwards/downwards, then moving them to a vertical position and holding it for a few seconds. This gesture may take time to hone due to it being a specific movement tracked by the Joy-Cons, but when it is matched, the system will check to see if flog is installed. When checked, an audio clip of a man saying "chokusetsu" ("直接"), the Japanese word for "direct", will play and the screen will cut to black and launch the 1984 NES title Golf. This emulator is unique in that it includes instructions in English and Japanese on how to play depending on how the Joy-Cons are held, and has a more simplistic appearance than the emulators that would be used for Nintendo Switch Online. Pressing the Home button while playing Golf will return you to the Home Screen without any visible software running there.

With Version 4.0.0, Nintendo removed all of the code required to launch flog and play Golf, but the company seemed unusually hesitant to even acknowledge its existence when asked by news outlets. One month before its removal, Nintendo of America president Reggie Fils-Amie released two statements regarding it when asked by Kotaku:


While this seems to allude that the secret emulator and Golf's inclusion were not authorized, this all but confirms that their purpose was to act as a tribute to Nintendo's late CEO Satoru Iwata. Iwata, who programmed Golf and previously hosted the Nintendo Direct showcase series, passed away on July 11, 2015, with the method to unlock the emulator mimicking a gesture he used during Nintendo Directs. Japanese fans on social media referred to the Easter egg as an "omamori", amulets that if kept close are said to protect the bearer and bring good luck, speculating that Golf was included by Iwata as a secret charm to watch over every Nintendo Switch unit after his death.

Multiple early "black box" NES releases' cartridges produced during the console's US launch in Winter 1985 didn't use NES ROM chips, but rather Famicom ROM chips with a built-in converter. The 15 NES launch titles, and the only games known to have these chips, are:

• 10-Yard Fight
• Baseball
• Clu Clu Land
• Duck Hunt
• Excitebike
• Golf
• Gyromite
• Hogan's Alley
• Ice Climber
• Kung Fu
• Pinball
• Stack-Up
• Tennis
• Wild Gunman
• Wrecking Crew

All of these games would eventually be reprinted with regular NES chips.