Boot modes - hack-different/qemu-xnu GitHub Wiki

The emulated T8030 machine uses a few boot modes to determine the root device

• auto: Make decision based on the auto-boot nvram variable. (the default mode)
  • If auto-boot is false/undefined, the device will boot the ramdisk in restore mode, which means adding the boot args : -restore rd=md0 nand-enable-reformat=1 -progress. Otherwise the boot args is unchanged.
• manual: Leave the boot args as user passed (-append).
• enter_recovery: Set auto-boot to false (drop to restore mode) and then behaves like auto on the following reboots.
• exit_recovery: Set auto-boot to true and then behaves like auto on the following reboots.

The auto mode will boot to restore mode until the restore succeeded and then boot to disk on the following (re)boots.

The enter_recovery mode exists to force a restore. Note that this set persistent nvram variable auto-boot. The exit_recovery mode can undo this.

Regardless of the boot modes,

• If no root device is defined through boot args (rd=), the device will automatically root to disk0s1 (If it is mountable).
• If the resulting boot args contains -restore, the device will identify as a DEV board to avoid restore issues.