README-Dev.md

RefindPlus

A Boot Manager for Mac and PC

   

Overview

RefindPlus builds on rEFInd to extend its functionality with enhancements and fixes that include several Apple Mac and UEFI-PC related items that may be of interest to anyone requiring a capable and flexible boot manager.

RefindPlus is particularly useful for those with additional configuration needs or that require advanced or otherwise non-typical options for running operating systems and uEFI utilities on Mac and PC.

Some features:

• Maintains feature and configuration parity with Upstream v0.14.2 base.
• Provides protection against damage to vulnerable Mac nvRAM by UEFI Windows boot.
• Provides mitigation against boot failures and related issues on T2/TPM chipped units.
• Provides Pre-Boot Configuration Screen on units running GPUs without native EFI on Macs.
• Emulates UEFI 2.x on EFI 1.x units to permit running UEFI 2.x utilities on such units.
• Extensive memory management improvements with associated speed and stability gains.
• Provides improved text display support for languages that require unicode text.
• Identifies and automatically handles Ventoy instances if present.
  • Rationalises binaries displayed.
  • Displays an os_ventoy icon if available.
• Adds a debug (DBG) binary that provides extensive logging.
  • The release (REL) binary is an optimised build for day to day use.
• Fixes inability to print to screen on some Macs.
  • This prevented receiving program messages or using utilities such as uEFI shell.
• Provides NVMe capability, if required, via an inbuilt NvmExpress driver.
  • Removes the need to load external drivers on units without native NVMe support.
  • Basically allows working as if NVMe is natively supported by the firmware.
• Provides APFS filesystem capability, if required, via an inbuilt APFS JumpStart driver.
  • Removes the need to load external drivers on units without native APFS support.
  • Additionally ensures matching APFS drivers for specific Mac OS versions are used.
  • Basically allows working as if APFS is natively supported by the firmware.
• Fully supports APFS filesystem requirements.
  • This allows booting recent Mac OS versions from single named volumes.
    • As opposed to generic and difficult to distinguish PreBoot volumes.
    • Avoids compromising system integrity by otherwise requiring SIP to be disabled.
  • This also allows booting FileVault encrypted volumes from single named volumes.
    • As opposed to generic and difficult to distinguish PreBoot volumes.

Installation

MyBootMgr is recommended to automate installing RefindPlus when running Mac OS on Intel-based Macs. Alternatively, as the RefindPlus efi file can function as a drop-in replacement for the upstream efi file, the rEFInd package can be installed first and its efi file replaced with the RefindPlus efi file (Ensure the RefindPlus efi file is renamed to match). This manual process allows installing RefindPlus on other operating systems supported upstream.

Note

MyBootMgr can optionally also be used to create a flexible and powerful RefindPlus|OpenCore chain-loading arrangement for MacPro3,1 to MacPro5,1 as well as for Xserve2,1 and Xserve3,1.

Upstream post-release code updates are typically ported to RefindPlus as they happen and as such, the RefindPlus code base is usually at the state of the base upstream release version plus any such updates. The code base typically also includes updates for subsequent upstream release versions since the base version.

Tip

Consider replacing upstream filesystem drivers with those packaged with RefindPlus as these are always either exactly the same as upstream versions or have had fixes applied.

RefindPlus will function with the upstream configuration file, refind.conf, but users may wish to replace this with the RefindPlus configuration file, config.conf, to configure the additional options provided by RefindPlus. A sample RefindPlus configuration file is available here: config.conf-sample-Dev.

Tip

RefindPlus-specific options can also be simply added to upstream configuration files.

When run without activating RefindPlus-specific configuration options, as will be the case with unmodified upstream configuration files, a RefindPlus run will be equivalent to running the upstream version it is based on. That is, the additional options provided in RefindPlus must be actively enabled if they are required.

Note

This equivalence is subject to a few divergent items as outlined under the Divergence Section below.

Additional Functionality

RefindPlus-specific funtionality can be configured using the tokens below.
Additional information is provided in the sample RefindPlus configuration file.
These tokens are included in Section 1 of the sample RefindPlus configuration file.

Token	Functionality
continue_on_warning	Proceed as if a key was pressed after screen warnings (for unattended boot)
csr_dynamic	Actively enables or disables Apple's System Integrity Protection (SIP)
csr_normalise	Removes the APPLE_INTERNAL bit, when present, to permit OTA updates
decline_help_icon	Disables feature that may improve loading speed by preferring generic icons
decline_help_size	Disables feature that sets additional UI scaling for very high DPI screens
decline_help_text	Disables feature that sets screen text to complementary colours
decouple_key_f10	Unmaps the F10 key from native screenshots (the \ key remains mapped)
disable_apfs_load	Disables inbuilt provision of APFS filesystem capability
disable_apfs_sync	Disables feature allowing direct APFS/FileVault boot (Without "PreBoot")
disable_check_amfi	Disables AMFI Checks on Mac OS if required
disable_check_compat	Disables Mac version compatibility checks if required
disable_pass_gop_thru	Disables feature that provides GOP instance on UGA for some loading screens
disable_legacy_sync	Disables detailed indentification of Mac legacy BIOS boot capability
disable_nvram_paniclog	Disables logging Mac OS kernel panics to nvRAM
disable_nvram_protect	Disables blocking of potentially harmful write attempts to Legacy Mac nvRAM
disable_reload_gop	Disables reinstallation of UEFI 2.x GOP drivers on EFI 1.x units
disable_rescan_dxe	Disables scanning for newly revealed DXE drivers when connecting handles
disable_set_applefb	Disables provision, under some circumstances, of missing Apple Framebuffers
disable_set_consolegop	Disables feature that fixes some issues with GOP graphics on legacy units
enable_esp_filter	Prevents other ESPs other than the RefindPlus ESP being scanned for loaders
force_trim	Forces TRIM on Third-Party SSDs on Macs if required
hidden_icons_external	Allows scanning for .VolumeIcon icons on external volumes
hidden_icons_ignore	Disables scanning for .VolumeIcon image icons if not required
hidden_icons_prefer	Prioritises .VolumeIcon and .VolumeBadge image icons when available
icon_row_move	Repositions the main screen icon rows (vertically)
icon_row_tune	Fine tunes the resulting icon_row_move outcome
mitigate_primed_buffer	Allows enhanced intervention to handle apparent primed keystroke buffers
nvram_protect_ex	Extends NvramProtect, if set, to Mac OS and unknown UEFI boots
nvram_variable_limit	Limits nvRAM write attempts to the specified variable size
pass_uga_through	Provides UGA instance on GOP to permit EFI Boot with modern GPUs
persist_boot_args	Overrides using vRAM (instead of nvRAM) for Mac OS boot argument items
prefer_uga	Prefers UGA use (when available) regardless of GOP availability
ransom_drives	Frees partitions locked by how certain firmware load inbuilt drivers
renderer_direct_gop	Provides a potentially improved GOP instance for certain GPUs
renderer_text	Provides a text renderer for text output when otherwise unavailable
scale_ui	Provides control of UI element scaling
screen_rgb	Allows setting arbitrary screen background colours
set_boot_args	Allows setting arbitrary Mac OS boot arguments
supply_nvme	Enables an inbuilt NvmExpress driver
supply_uefi	Enables feature that emulates UEFI 2.x support on EFI 1.x units
sync_nvram	Resets nvRAM settings, such as BlueTooth, on some boot types if required
sync_trust	Works around some Boot Chain of Trust problems on T2/TPM chipped units
transient_boot	Disables feature that highlights the last booted loader by default
unicode_collation	Provides fine tuned support for languages that use unicode text

Modified Functionality

In addition to the new functionality listed above, the following upstream tokens have been modified:

• "timeout": The default is no timeout unless explicitly set.
• "use_nvram": RefindPlus variables are written to the file system, not the motherboard's nvRAM chip, unless explicitly set to do so by activating this configuration token.
• "use_graphics_for": Additional options added:
  • tools option to enable graphics mode loading for such.
  • none option to disable graphics mode loading for everything.
  • everything option to enable graphics mode loading for everything.
  • OpenCore and Clover can be specifically set to load in graphics mode.
• "showtools": Additional tool added:
  • clean_nvram : Allows resetting nvRAM directly from RefindPlus.
    • When run on Apple firmware, RefindPlus will additionally trigger nvRAM garbage collection
• "csr_values": A value of 0 can be set as the Enabled value to allow Over The Air (OTA) updates when running Mac OS 11.x (Big Sur), or later, with SIP enabled.
  • This is equivalent to activating the csr_normalise token.
• "log_level": Controls the native log format and an implementation of the upstream format.
  • Only active on DEBUG and NOOPT builds while RELEASE builds remain optimised for day-to-day use.
  • Level 0 does not switch logging off but activates the native summary format.
  • Levels 1 and 2 output logs similar to the detailed upstream format.
    • Level 1 is broadly equivalent to upstream Level 4 (upstream Levels 1 to 3 were dispensed with)
    • Level 2 is only exposed on NOOPT builds and outputs logs at a very detailed level
      • Create NOOPT builds by passing ALL or NPT as a second parameter to the RefindPlus build script
        • Setting ALL includes an NPT build to the standard REL and DBG builds created
        • Setting NPT creates only that build type
          • Applies to setting REL or DBG
      • The first parameter is the build branch, which also needs to be specified in such instances
    • When Level 2 is not exposed, selected levels above 1 will be capped at Level 1
    • When exposed, selected levels above 2 will be capped at Level 2
• "resolution": The max setting is redundant in RefindPlus which always defaults to the maximum available resolution whenever the resolution is not set or is otherwise not available.
• "screensaver": The screensaver cycles through a set of colours as opposed to a single grey colour.

Divergence

Significant visible implementation differences vis-a-vis the upstream base are:

• GZipped Loaders: RefindPlus only provides stub support for handling GZipped loaders as this is largely only relevant for units on the ARM architecture.

  • This stub support is only used for debug logging in RefindPlus and can be activated using the same support_gzipped_loaders configuration token as upstream.

• Screenshots: These are saved in the PNG format with a significantly smaller file size.

  • Additionally, the file naming is slightly different and the files are always saved to the same ESP as the RefindPlus efi file.

• UI Flags: RefindPlus requires that any desired previously set hideui configuration token options are explicitly defined in supplementary/theme configuration files; as whenever the token is found in such files, the token setting is reset by RefindPlus to the specified option(s). The upstream implementation effectively adds new settings to any previously existing ones for this configuration token instead.

  • The RefindPlus implementation maintains consistency with how other configuration tokens are handled.

• UI Scaling: WQHD monitors are correctly determined not to be HiDPI monitors and UI elements are not scaled up on such monitors when the RefindPlus-specific scale_ui configuration token is set to automatically detect the screen resolution. RefindPlus also takes vertically orientated screens into account and additionally scales UI elements down when low resolution screens (less than 1025px on the longest edge) are detected.

  • Additionally, UI elements on extremely high resultion screens (greater than 5999px on the longest edge) receive a 4X scaling as opposed to the 2X scaling applied for standard HiDPI screens.

• Loader Icons: RefindPlus defaults to preferring generic icons for loaders ahead of the slower to load custom icons where possible. The upstream icon search implementation involves only loading such icons after a search for custom icons has not turned anything up.

  • Activate the RefindPlus-specific decline_help_icon configuration token to use the upstream icon search implementation instead of the RefindPlus default.

• GOP Driver Provision: RefindPlus attempts to ensure that UEFI 2.x GOP drivers are available on EFI 1.x units by attempting to reload such drivers when it detects an absence of GOP on such units to permit the use of modern GPUs on legacy units.

  • Activate the RefindPlus-specific disable_reload_gop configuration token to switch this feature off.

• Apple Framebuffer Provision: RefindPlus defaults to always providing Apple framebuffers on Macs, when not available under certain circumstances. This is done using an inbuilt SetAppleFB feature.

  • Activate the RefindPlus-specific disable_set_applefb configuration token to switch this feature off.

• APFS Filesystem Provision: RefindPlus defaults to always providing APFS Filesystem capability, when not available but is required, without a need to load an APFS driver. This is done using an inbuilt SupplyAPFS feature.

  • Activate the RefindPlus-specific disable_apfs_load configuration token to switch this feature off.

• APFS PreBoot Volumes: RefindPlus always synchronises APFS System and PreBoot partitions transparently such that the Preboot partitions of APFS volumes are always used to boot APFS formatted Mac OS. Hence, a single option for booting Mac OS on APFS volumes is presented in RefindPlus to provide maximum APFS compatibility.

  • Activate the RefindPlus-specific disable_apfs_sync configuration token to switch this feature off.

• Mac nvRAM Protection: RefindPlus always prevents UEFI Windows Secure Boot from saving certificates to Mac nvRAM as this can result in damage and an inability to boot. Blocking these certificates does not impact the operation of UEFI Windows on Macs. This filtering only happens when Mac firmware is detected and is not applied to other types of firmware.

  • Activate the RefindPlus-specific disable_nvram_protect configuration token to switch this feature off.

• Mac Legacy BIOS Boot: RefindPlus originally assumed all Macs were capable of legacy BIOS boot based on code that went in upstream back in 2012 when this was a reasonable default. However, some later Intel Macs do not support legacy BIOS boot and RefindPlus now attempts to categorise Macs to enable/disable legacy boot accordingly.

  • Activate the RefindPlus-specific disable_legacy_sync configuration token to base legacy BIOS boot availability on the old assumption.

• Secondary Configuration Files: While the upstream documentation prohibits including tertiary configuration files from secondary configuration files, there is no mechanism enforcing this prohibition. Hence, tertiary, quaternary, quinary, and more, configuration files can in fact be included.

  • The RefindPlus implementation enforces the limitation for inclusion to secondary configuration files.

• Shortcut Keys: RefindPlus does not allocate shortcut keys based on the operating system type/name as there is no way of knowing what would actually be loaded in many cases.

  • Tools are not allocated shortcut keys with the exception of Key A allocated to About Refindplus and Key Z allocated to System Shutdown.

  • For loaders, keys are allocated based on display position in the order of Key 1 to Key Y. Alphabetical Keys I and O are not used while Numeric Key 0 is reserved for internal use.

• Disabled Manual Stanzas: The processing of a user configured boot stanza is halted, and the Entry object immediately discarded, once a Disabled setting is encountered. The outcome is the same as upstream, which always continues to create and return a fully built object in such cases to be discarded later. The approach adopted in RefindPlus allows for an optimised loading process particularly when such Disabled tokens are placed immediately after the menuentry line (see examples near the bottom of the config.conf-sample-Dev file).

  • This also applies to submenuentry items which can be enabled or disabled separately.

• Pointer Device Priority: The upstream implementation of pointer device priority is based on how the enable_mouse and enable_touch pointer device control tokens appear in the configuration file(s) when both are active. The last pointer device control token read in the main configuration file and/or any supplementary/override configuration file will be used and the other disregarded. In RefindPlus however, enable_touch always takes priority when both tokens are active without regard to the order of appearance in the configuration file(s).

  • Hence, to use a mouse in RefindPlus, enable_touch must be disabled (default) in addition to enabling enable_mouse.

Roll Your Own

Refer to BUILDING.md for build instructions.

CLICK HERE for the ReadMe file related to the current (work in progress) code base.