Hacking Recover formatted hard drive?

[SpaceJump]

Do I understand correctly that it's possible to not have the Wii U ask for formating? I have a 2TB HDD with 2 partitions (1 wbfs, 1 FAT32 for WiiMC).

 

[fatcatfan]

The report of the HPA was wrong, he redid the tests later and said it worked.

Doh! I wish I'd caught that before I spent yesterday evening recompiling kernel to re-enable IDE_TASK_IOCTL for hdparm.

Actually I was wrong earlier. It doesn't block drives with HPA, it DOES block GPT drives where it can't find the backup table (since it needs to delete it I guess)

Based on his previous tests, maybe another solution is a GPT'd drive with the backup table zeroed out? Using a hybrid MBR so unmodified usb loaders can find the partitions. Then it's really a matter of how different OSes respond to that when the drive is plugged into a PC. Hopefully none automatically repair/rewrite the backup GPT when the drive is connected. (http://www.rodsbooks.com/gdisk/hybrid.html#reactions)

Sorry, I know these theorizing posts don't help anything without some test to prove it one way or another. These I know I can easily test tonight without having to recompile kernel. I'm hoping to find a "set once and forget about it" solution to use a HDD only for backup with the vWii while eliminating the formatting prompt, which can be used right now. It's only a matter of time before my kids accidentally format the drive when prompted, like steven here, and constantly having to plug and unplug the drive reduces the convenience of having it in the first place.

 

[Cyan]

GPT is not compatible with all computers/OS (Windown XP doesn't work with GPT), so forcing GPT for users is not a good solution either.

Replacing the partition table signature from 0x55AA to 0x55AB is currently working fine (except for WBFS partitions and EmuNAND on USB).
But I don't like the idea to write the sector 0 on user's HDD. I don't want to be blamed for lost data.

 

[fatcatfan]

I absolutely agree either solution (yours or mine) involves something of a risky hack and isn't for everyone. I just want it to work for me But:

XP 64-bit can read GPT. XP 32-bit can read the hybrid, GPT protective MBR used by BootCamp for dual-booting Windows on a Mac.
http://msdn.microsoft.com/en-us/library/windows/hardware/gg463525.aspx

Q. Can Windows XP x64 read, write, and boot from GPT disks?
A. Windows XP x64 Edition can use GPT disks for data only.

Q. Can the 32-bit version of Windows XP read, write, and boot from GPT disks?
A. No. The 32-bit version will see only the Protective MBR. The EE partition will not be mounted or otherwise exposed to application software.

For a < 2 TB drive with only 1 or 2 necessary PC / vWii accessible partitions (as would likely be the case for my intended usage) the hybrid MBR can exactly match the GPT in number and size of partitions.

 

[fatcatfan]

Replacing the partition table signature from 0x55AA to 0x55AB is currently working fine (except for WBFS partitions and EmuNAND on USB).

This is not working for me on a flash drive. I still get prompted to format when the Wii U restarts.

Zeroing out the backup GPT also didn't work for me; still got the Wii U format prompt. Perhaps what KDH saw before was a result of the HPA... the location of the backup GPT specified in the primary GPT would have been beyond the limits of drive, in the HPA.

 

[DeadMan]

This is not working for me on a flash drive. I still get prompted to format when the Wii U restarts.

Zeroing out the backup GPT also didn't work for me; still got the Wii U format prompt. Perhaps what KDH saw before was a result of the HPA... the location of the backup GPT specified in the primary GPT would have been beyond the limits of drive, in the HPA.

last day's i use USB HDD with 55AB in last two bytes in sector 0 (MBR) and don't see any prompt. In my test, WiiU check only this bytes, and if it's 55AA it ask about format.
I fill all space of my USB flash with zero byte, insert it in WiiU and don't get prompt about format. After that i change last two bytes of the sector 0 to 55AA, insert USB flash to WiiU and now i got the prompt. WiiU check only this signature, i think

 

[fatcatfan]

last day's i use USB HDD with 55AB in last two bytes in sector 0 (MBR) and don't see any prompt. In my test, WiiU check only this bytes, and if it's 55AA it ask about format.
I fill all space of my USB flash with zero byte, insert it in WiiU and don't get prompt about format. After that i change last two bytes of the sector 0 to 55AA, insert USB flash to WiiU and now i got the prompt. WiiU check only this signature, i think

It's working for me now. I must have been mistaken. Something else I was doing may have been replacing the correct signature before I moved the flash to the WiiU.