Toggle for SD mount on boot

[Kannix2005]

Requirements

Description

SD Card mounting on boot can be disabled. This is useful if you regularily want to flash a firmware via internal SD-Card Reader with the FirmwareUpdater Plugin in Octoprint. The mounting of the SD on a RPi requires you to have the SD card not mounted in Marlin.

Benefits

No need to release the media every time the printer reboots.

Configurations

Configuration.h adapted and pushed as well.

Related Issues

[rhapsodyv]

When the board have MSC support (to allow it mount on the computer), it automatically disable SD detect, making it don't mount on boot.

/**
 * Override the SD_DETECT_STATE set in Configuration_adv.h
 * and enable sharing of onboard SD host drives (all platforms but AGCM4)
 */
#if ENABLED(SDSUPPORT)

  #if SD_CONNECTION_IS(ONBOARD) && DISABLED(NO_SD_HOST_DRIVE) && !defined(ARDUINO_GRAND_CENTRAL_M4)
    //
    // The external SD card is not used. Hardware SPI is used to access the card.
    // When sharing the SD card with a PC we want the menu options to
    // mount/unmount the card and refresh it. So we disable card detect.
    //
    #undef SD_DETECT_PIN
    #define HAS_SHARED_MEDIA 1
  #endif

Said that, I don't know what is your issue.

[thinkyhead]

When there's no SD_DETECT_PIN, Marlin will always try to mount the media at startup by pure trial-and-error.