Microsoft
We are sorry to hear that you are having issues with build 9879 of Windows Technical Preview. As part of our expansion of the Instant Go feature to devices with Hybrid Hard Drives (drives that have both SSD FLASH and spinning media) we added a command that turns on the drive’s Power-Up in Standby (PUIS) feature. This gives more power savings. In this mode, the drive does not spin-up when power is applied, but only once it receives a spin-up command. This command is sent by the system’s BIOS during startup or on resume from Sleep/Hibernate.
It turns out that there are a few BIOS implementations that do not send the needed PUIS spin-up command and we had a bug in which we enabled PUIS not only on Hybrid Hard Drives, but on all Hard Disk Drives (HDD). Because those BIOS implementations do not send the spin-up command, they either are unable to identify the drive during boot and ultimately fail to start Windows or are unable to find the drive during resume from Sleep/Hibernate and the machine freezes.
The system must have the following configuration to hit this issue:
The drive must be a SATA HDD.
The drive must support Power-Up in Standby (PUIS) where the HDD keeps its platter spun down when the disk gets powered up.
The system must be running the in-box SATA driver, StorAHCI.
The system is running the Windows Technical Preview build 9879.
The system BIOS does not send a spin-up command after power on and/or after resume.
There are two possible symptoms, each of which is dependent upon the BIOS:
On powering up your system, depending on your BIOS, you see a message saying; “No boot device…” or something similar.
This occurs when on boot the BIOS does not issue a PUIS spin-up command to the HDD before querying for Identify Data. Thus, the HDD does not return enough data for the BIOS to properly identify, initialize, and ultimately boot from the HDD.
The system boots without issue but hangs (spinning dots) upon resuming from sleep or crashes with a d1, 7a, or 7b error code.
In this case the BIOS *does* send the PUIS spin-up command on boot. This distinguishes it from symptom #1.
This issue with resume from sleep occurs because the BIOS doesn’t issue a PUIS spin-up command upon resume, either because it can’t or it simply doesn’t. The Microsoft inbox SATA driver fails to start the drive’s port because the disk is spun-down.
We have a fix ready and it is a part of KB3021937. If you are experiencing symptom #2, then you will need to download and install the KB, keeping the computer awake through the whole process. If you are experiencing symptom #1, you will first need to get PUIS disabled on the HDD to allow it to boot.
The best way to do this is to use a 3rd party tool that can turn PUIS on and off such as the hdparm Tool for Windows.
To use hdparm:
Download the hdparm installer for your architecture (32-bit or 64-bit) from
http://disablehddapm.blogspot.com/
Install hdparm with the installer you downloaded above.
Start Disk Management (WIN+X, then K).
Determine which disk # maps to the disk that needs PUIS disabled.
Run an elevated command prompt (WIN+X, then A).
In the command prompt, run the following in order:
cd %systemdrive%"\Program Files (x86)\hdparm"
hdparm.exe -s 0 hd[a-z]
[a-z] is a single letter that maps to the disk number. E.g. if your disk # is 0 then you would use “hda”, if your disk # is 1 then you would use “hdb”, etc.
Note: if you can’t get your system to boot, then you will need to remove the disk from the current system and install it into a separate system and run the tool on the drive there.
Sincerely,
The Windows Storage Team
