keeping firmware time after linux mint, going back to windows

All Gurus once were Newbies
Forum rules
There are no such things as "stupid" questions. However if you think your question is a bit stupid, then this is the right place for you to post it. Please stick to easy to-the-point questions that you feel people can answer fast. For long and complicated questions prefer the other forums within the support section.
Before you post please read how to get help
Post Reply
green_dragon34
Level 1
Level 1
Posts: 13
Joined: Tue Jul 10, 2018 9:43 am

keeping firmware time after linux mint, going back to windows

Post by green_dragon34 »

I boot Linux Mint from USB. When I turn computer off and reboot to Windows, the system clock, firmware shows the wrong time by several hours. This seems to mess with the algorithm to recharge the battery Windows. Mostly it is annoying for me to have to change the clock every time I boot back into Windows, or another Linux distro.

How can I keep mask the right time in Linux Mint 19 Tara, and not change the firmware clock?
User avatar
Pierre
Level 20
Level 20
Posts: 10719
Joined: Fri Sep 05, 2008 5:33 am
Location: Perth, AU.

Re: keeping firmware time after linux mint, going back to windows

Post by Pierre »

it does seem that most Linux systems do stick to using GMT as their Time Base,
& whereas the Windows System usually uses Local Time - which varies, of course.

you will find that it's the Windows System, that is causing your Time issue.

this can be fixed in either system, but you most likely could set the Windows System, to be using GMT:
https://askubuntu.com/questions/232405/ ... ime#232452
from an Linux Forum, of course.
Image
Please edit your original post title to include [SOLVED] - when your problem is solved!
and DO LOOK at those Unanswered Topics - - you may be able to answer some!.
User avatar
Lord Boltar
Level 5
Level 5
Posts: 711
Joined: Mon Jan 09, 2017 7:24 pm
Location: Sunny Florida

Re: keeping firmware time after linux mint, going back to windows

Post by Lord Boltar »

This happens as Linux Buntu based OS interprets the hardware clock or real time clock (RTC) in universal time (UTC) by default while Windows 10 maintains the clock in local time, hence the time difference. As far as I know there is no fix for this running from a Live USB but you can if it was a dual boot system.
IF your problem has been solved, please edit your original post and add [SOLVED] to the beginning of the Subject Line. It helps other members

The only way for evil to prosper is for good men to do nothing
green_dragon34
Level 1
Level 1
Posts: 13
Joined: Tue Jul 10, 2018 9:43 am

Re: keeping firmware time after linux mint, going back to windows

Post by green_dragon34 »

As I think on it, if Mint Linux Tara can change the firmware clock, what else can it change in the basic BIOS/EFi firmware? is this a security consideration?
AscLinux
Level 4
Level 4
Posts: 342
Joined: Sat Oct 29, 2016 3:32 pm

Re: keeping firmware time after linux mint, going back to windows

Post by AscLinux »

Windows is known to make changes in firmware without any warning. Linux does not. In case of clock, it is hwclock utility which can read and write clock into firmware. That's all it can do. And it requires elevated privileges for this. Try for yourself, open a terminal window and execute hwclock.
User avatar
karlchen
Level 21
Level 21
Posts: 13079
Joined: Sat Dec 31, 2011 7:21 am
Location: Germany

Re: keeping firmware time after linux mint, going back to windows

Post by karlchen »

green_dragon34 wrote:
Thu Nov 01, 2018 7:18 am
I boot Linux Mint from USB. When I turn computer off and reboot to Windows, the system clock, firmware shows the wrong time by several hours.
Confirmed.
Linux assumes that the hardware clock runs in the timezone UTC.
Windows assumes that the hardware clock runs in your local timezone.
As soon as Linux has got the chance to check and correct your system time by contacting an NTP server, it will do so and your hardware clock will be set to UTC.
Next time you boot your Windows you will notice the incorrect system time as a consequence.
Yet. As soon as Windows has got the chance to check and correct your system time by contacting an NTP server, it will do so and your hardware clock will be set to your local timezone again.

At least this is how it works here.
Image
Linux Mint 19.3 64-bit Cinnamon, Total Commander 9.51 64-bit
Haß gleicht einer Krankheit, dem Miserere, wo man vorne herausgibt, was eigentlich hinten wegsollte. (Goethe)
User avatar
Pierre
Level 20
Level 20
Posts: 10719
Joined: Fri Sep 05, 2008 5:33 am
Location: Perth, AU.

Re: keeping firmware time after linux mint, going back to windows

Post by Pierre »

Yep - that's how it works, here as well.
8)

if you are on-line, then just wait & either system will correct your system time by contacting an NTP server.
- after just a few minutes of being on-line.
:)
Image
Please edit your original post title to include [SOLVED] - when your problem is solved!
and DO LOOK at those Unanswered Topics - - you may be able to answer some!.
AscLinux
Level 4
Level 4
Posts: 342
Joined: Sat Oct 29, 2016 3:32 pm

Re: keeping firmware time after linux mint, going back to windows

Post by AscLinux »

I'd say more elegant way is to set Linux to use local time or to set Windows to use UTC. Both solutions are viable.
pbear
Level 14
Level 14
Posts: 5422
Joined: Wed Jun 21, 2017 12:25 pm
Location: San Francisco

Re: keeping firmware time after linux mint, going back to windows

Post by pbear »

I wonder which version of Windows the OP is using and whether he (or she) has disabled updates. I used to have this problem with Win10, but am unable to reproduce it now. Actually, I don't recall having a problem with live boots, but definitely full installs. No idea what may have changed or when, as it has been part of my routine for more than a year when I do full install to USB to set it to use local time with timedatectl set-local-rtc 1.

In light of karlchen and Pierre's comments, I reverted a couple of those to UTC (timedatectl set-local-rtc 0), booted on the Win10 box and observed the effect on system clock. To my astonishment, the effect was NONE. Not just that Windows was able to recover the correct time by syncing to the internet. Was displaying correct time before had brought up its WiFi connection. Thing is, I'm certain this used to be a problem, which is what sent me searching to find the timedatectl solution. Have had at least three major Win10 updates since then, though, so who knows what may have changed.

Or maybe I've dropped through a wormhole into an alternate universe.
Post Reply

Return to “Newbie Questions”