> For the complete documentation index, see [llms.txt](https://help.boomerang3.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.boomerang3.com/s2gw-installation-manual/advanced_use/s2gw_application_upgrade/write-app-to-sd-card.md).
# Write app to SD card
To do this perform the following steps:
1. Disconnect power from S2GW.
2. Remove the SD card from S2GW.
3. Connect the SD card to a card reader.
4. There are 2 partitions on the SD card and only one of them is readable by Windows. Windows will propose to format the other one, do not do it and click “Cancel”.
5. Look for “boot” partition (drive K: in example). Please note that the drive letter may be different in your case.
6. Open boot:\ICU folder in Explorer. There shall be only nodeservers.xml file there.
7. Put the new software version files in this directory.
7. Remove SD card from the card reader and insert it into S2GW socket.
8. Connect power to S2GW.
9. S2GW shall start automatically.
10. The files, placed in boot:\ICU folder, are moved to their proper locations after S2GW start so if you will check the directory again there will be only nodeservers.xml file.
---
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