# How do I flash an image to emmc on rsb-3720?
**URL:** https://forum.aim-linux.advantech.com/t/how-do-i-flash-an-image-to-emmc-on-rsb-3720/533
**Category:** Technical Supports
**Created:** [September 4, 2023, 8:57am UTC](https://forum.aim-linux.advantech.com/t/how-do-i-flash-an-image-to-emmc-on-rsb-3720/533 "2023-09-04T08:57:27Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@Tetsuya\_Kawahara](https://forum.aim-linux.advantech.com/u/Tetsuya_Kawahara)
#### Post date: [September 4, 2023, 8:57am UTC](https://forum.aim-linux.advantech.com/t/how-do-i-flash-an-image-to-emmc-on-rsb-3720/533/1 "2023-09-04T08:57:27Z")
I have experience flashing images built with imx-image-full to SD cards.
However, I’m not sure how to flash an image to emmc.
Which part of the wiki does this fall under?
[http://ess-wiki.advantech.com.tw/view/IoTGateway/BSP/Linux/iMX8/Yocto\_LBVC\_User\_Guide#Build\_U-Boot\_in\_standalone\_environment](http://ess-wiki.advantech.com.tw/view/IoTGateway/BSP/Linux/iMX8/Yocto_LBVC_User_Guide#Build_U-Boot_in_standalone_environment)
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### Author:  [@Tetsuya\_Kawahara](https://forum.aim-linux.advantech.com/u/Tetsuya_Kawahara)
#### Post date: [September 4, 2023, 11:14am UTC](https://forum.aim-linux.advantech.com/t/how-do-i-flash-an-image-to-emmc-on-rsb-3720/533/2 "2023-09-04T11:14:30Z")
Also, do you know how to make it a read-only file system except for /etc and /home/root?
I’m in the process of looking into this using yocto kirkstone’s overrayfs and overrayfs-etc based on the following site.
[https://mickey-happygolucky.hatenablog.com/entry/2022/12/02/032345](https://mickey-happygolucky.hatenablog.com/entry/2022/12/02/032345)
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### Author:  [@Jems\_Cheng](https://forum.aim-linux.advantech.com/u/Jems_Cheng)
#### Post date: [September 5, 2023, 9:24am UTC](https://forum.aim-linux.advantech.com/t/how-do-i-flash-an-image-to-emmc-on-rsb-3720/533/3 "2023-09-05T09:24:05Z")
Hi~
Please check the wiki user guide: Reflash EMMC from Boot SD CARD
[Yocto Linux BSP Ver.C User Guide for iMX8 series -Yocto 4.0 - ESS-WIKI (advantech.com.tw)](http://ess-wiki.advantech.com.tw/view/IoTGateway/BSP/Linux/iMX8/Yocto_LBVC_User_Guide#Reflash_EMMC_from_Boot_SD_CARD)
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### Author:  [@Tetsuya\_Kawahara](https://forum.aim-linux.advantech.com/u/Tetsuya_Kawahara)
#### Post date: [September 5, 2023, 10:23am UTC](https://forum.aim-linux.advantech.com/t/how-do-i-flash-an-image-to-emmc-on-rsb-3720/533/4 "2023-09-05T10:23:40Z")
Hi @Jems_Cheng
Thank you for your information.
I didn’t think there was a way to flash it on another wiki.
[http://ess-wiki.advantech.com.tw/view/RSB-3720\_user\_guide](http://ess-wiki.advantech.com.tw/view/RSB-3720_user_guide)
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### Author:  [@Jems\_Cheng](https://forum.aim-linux.advantech.com/u/Jems_Cheng)
#### Post date: [September 11, 2023, 6:41am UTC](https://forum.aim-linux.advantech.com/t/how-do-i-flash-an-image-to-emmc-on-rsb-3720/533/5 "2023-09-11T06:41:28Z")
It can reference the Yocto menu to create a Read-only Root Filesystem.
[https://docs.yoctoproject.org/dev/dev-manual/read-only-rootfs.html](https://docs.yoctoproject.org/dev/dev-manual/read-only-rootfs.html)
For areas with write access, that can reference 30.3.
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### Author:  [@Tetsuya\_Kawahara](https://forum.aim-linux.advantech.com/u/Tetsuya_Kawahara)
#### Post date: [September 11, 2023, 8:49am UTC](https://forum.aim-linux.advantech.com/t/how-do-i-flash-an-image-to-emmc-on-rsb-3720/533/6 "2023-09-11T08:49:10Z")
Data written in /tmp or /var will be volatile.
I forgot to mention that the written data must also be retained even after the power is turned off.
Also, the data may be rewritten while the power is on.
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### Author:  [@Jems\_Cheng](https://forum.aim-linux.advantech.com/u/Jems_Cheng)
#### Post date: [September 13, 2023, 2:52am UTC](https://forum.aim-linux.advantech.com/t/how-do-i-flash-an-image-to-emmc-on-rsb-3720/533/7 "2023-09-13T02:52:17Z")
Hi~
According to the Linux file system hierarchy standard, regardless of whether rootfs is set to read-only, the data stored in the /tmp directory may be deleted every time the system is started.
> **[fhs-3.0.pdf](https://refspecs.linuxfoundation.org/FHS_3.0/fhs-3.0.pdf)**
>
> 243.11 KB
You want to write to a rootfs (partition) that has been set to read-only, which is a conflicting operation. I think it can only be written after you set up read/write, or it can add an extra place to store the retained data. The following example creates mmcblk1p3 for writing and persisting data in a read-only rootfs.
