[Debian Bug] FAT32 Timestamp Offset Issue

FAT32 should be saved using localtime instead of UTC, designed by microsoft. However, FAT32 in Raspbian Version of Linux is saving timestamp with UTC time even without

tz=UTC

option in the /etc/fstab file.

In particular case, the Raspberry Pi records time that shows a 2 hour lags on Windows, which is the time difference between localtime and UTC.

This is an known bug, and developers are generally not actively fixing the bug, unfortunately.

Methods that doest work…

1.

/etc/defualt/rcS, add
> UTC=no

2. Seems lik RTC does not exist on Raspberry Pi…

> hwclock --systohc --utc
> hwclock --hctosys --utc

 

Workaround: time_offset=minutes

Set offset for conversion of timestamps from local time used by FAT to UTC. I.e. <minutes> minutes will be subtracted from each timestamp to convert it to UTC used internally by Linux. This is useful when time zone set in sys_tz is not the time zone used by the filesystem. Note that this option still does not provide correct time stamps in all cases in presence of DST – time stamps in a different DST
setting will be off by one hour.

https://www.kernel.org/doc/Documentation/filesystems/vfat.txt

For this case, adding time=offset=120 in

/etc/fstab

fix the timestamp problem. No change in

/etc/defualt/rcS

is needed.

 

Appended working fstab

proc /proc proc defaults 0 0
/dev/mmcblk0p6 /boot vfat defaults 0 2
/dev/mmcblk0p7 / ext4 defaults,noatime 0 1
# a swapfile is not a swap partition, no line here
# use dphys-swapfile swap[on|off] for that
UUID=BCF3-B0C0 /media/pi/TRANSCEND vfat auto,rw,nofail,time_offset=120 0 0

 

 

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