wrote:
Think Engineering has provided a temporary workaround to resolve the double POST experienced during boot up on P50 and P70 ThinkPads.
The workaround requires the I/O Port Access to be disabled in BIOS.
- Reboot the system and press F1 to enter BIOS Setup
- Change to “Security” page
- Change to “I/O Port Access” section
- Scroll down to “Wireless WAN”, press Enter, and then set to “Disabled” as shown
The root cause is being confirmed and Think Engineering is working on a permanent fix that will be provided via BIOS update.
I have just updated to the just released 2.0/1.15 BIOS/EC for P70.
I was curious to see if the genuine fix for the P70 double-boot symptom might have been included. Note that this symptom has only been seen by me on my P70 when powering up for the first time from a cold power-OFF state. For all other reboots when the machine was already powered ON, only normal single-boots were present.
I had been advised of this Security -> I/O port access -> Wireless WAN = DISABLED workaround last week, and it DID solve my own P70 double-boot symptom.
And not only did it prevent double-boots, but boot time in general with this WWAN option DISABLED was DRAMATICALLY REDUCED from what it had previously been. Both cold boot and soft re-boot times were significantly improved, with Lenovo logo screen to Windows Boot Manager now remarkably down around 3 seconds. [Note that I don't have any HDD spinners in my P70, but instead have two Samsung 950 Pro NVMe drives and one Samsung 850 Pro SATA3 SSD.]
Anyway, I want to report that experience on this double-boot symptom after upgrading to BIOS 2.0 was that the UNDERLYING CAUSE OBVIOUSLY STILL HAS NOT BEEN RESOLVED. In other words, trying to go back to the default WWAN = ENABLED using BIOS 2.0 once again brings back the unwanted double-boot symptom and slower overall time from Lenovo logo to Windows Boot Manager. Reverting back to WWAN = DISABLED once again makes the double-boot symptom disappear while also greatly reducing time from Lenovo log to Windows Boot Manager.
Note that I have been running with the BIOS option of "boot mode = QUICK" (which produces the Lenovo logo screen at boot) ever since discovering that "boot mode = DIAGNOSTICS" interfered with the two boots involved in the BIOS update process (one for the BIOS update, then a reboot, and then a second for the EC update). This has now been confirmed by Think engineering to be a more global BIOS symptom affecting other Skylake boards, and results in a permanent machine HANG during that inter-step reboot between BIOS and EC (only finally overcome by first pulling out the power cord and now re-booting).
Once I reverted back to "boot mode = QUICK", the 2-step BIOS update process now completes flawlessly, although the desired diagnostics screen info is no longer seen of course. Not a serious issue, and the Lenovo logo screen is just fine.
Coupled with the WWAN = DISABLED setting which, for me, absolutely eliminates the double-boot from cold power-OFF state symptom, along with the significantly reduced time from Lenovo logo to Windows Boot Manager, this is just how I will be running from now on. Machine runs great.