303
edits
Changes
why does nintendo do this (I've confirmed that the flag in HW_RESETS is set by MIOS in some cases, and that boot2 reads that flag and sets 00003164 based on (uint)(-1 < iVar2 << 0x1a) => presence of bit 5/0x20 => SRSTB_CPU, but am unclear on how it exactly works). Also remove the BC part (it's /dev/es's ES_LaunchBC); clarify the dead code
Line 2:
Line 2:
+
+
{{Stub}}
{{Stub}}
−'''boot2''' is the [[Wii]]'s third-stage bootloader. It is responsible for loading the [[System Menu]] [[TMD]] and loading the appropriate [[IOS]] under normal circumstances, although it can also load [[MIOS]] if it detects the lowered clock speed set by [[BC]] (if [[IOS/Syscalls|syscall 55]] returns 162), and it can simply shut down if it detects a flag{{check}} set by MIOS. There is also a path that loads BC, although it appears unused.
+'''boot2''' is the [[Wii]]'s third-stage bootloader. It is responsible for loading the [[System Menu]] [[TMD]] and loading the appropriate [[IOS]] under normal circumstances, although it can also load [[MIOS]] if it detects the lowered clock speed set by [[BC]] (if [[IOS/Syscalls|syscall 55]] returns 162).
+boot2 is also launched by MIOS when the power button is pressed; the System Menu is initialized in this case, and [[Memory Map|0x80003164]] <!-- read as c0003164 by the system menu; written as 00003164 by boot2 --> is set to 1 if the SRSTB_CPU bit is set in [[Hardware/Hollywood_Registers#HW_RESETS|HW_RESETS]]; the System Menu checks 0x80003164 and shuts down if it is enabled and [[:/title/00000001/00000002/data/state.dat|state.dat]] is set appropriately, with the message "Shutdown system from GC!".
+boot2 is built from the same code as a regular IOSes, but has a [[IOS/Syscalls|kernel flavor]] (syscall 47) of 0 instead of 3; boot2's ES module includes all of the [[:/dev/es|normal ES functionality]] but it goes unused due to this kernel flavor value. Regular IOSes also have the same check for a flavor less than 3, but the bootmii path goes unused.
There are two copies of boot2 housed in [[Hardware/NAND|NAND]] blocks 1-7 in case of failure, loaded by [[boot1]]. Additionally, a copy of boot2 may exist as title 1-1 in the NAND filesystem.
There are two copies of boot2 housed in [[Hardware/NAND|NAND]] blocks 1-7 in case of failure, loaded by [[boot1]]. Additionally, a copy of boot2 may exist as title 1-1 in the NAND filesystem.