Strange issue when accessing external SD card in Android car headunit

[tmihai20]

Hello. I have recently bought a new Android head unit based on Android 10, although the reported Android version is 12. I installed TC on it and it seems that TC for Android cannot write to the SD card. It can write to internal storage, but not on the mounted SD card. There is a File Manager app from the manufacturer that can write to SD card, but it is quite difficult to use. I checked if TC had the Storage permission and it does. What else can I do or check? It is really annoying having to use that app instead of TC.

[ghisler(Author)]

The file manager permission which gives write rights to all drives only exists on Android 11 and newer.
On Android 10 and older, the only way to write to the card is with SAF (Storage Access Framework). Try accessing the SD Card by clicking on "Add custom location" in the TC home folder. Then navigate to the root of the SD card and add it via the button at the bottom.

[tmihai20]

I will try that suggestion the next time I will be in the car. I installed another application and when it tried to access the SD card through and USB adapter it had a dialogue that yielded a "App not found" message. I wrote the seller of the head unit and told them to include it in a future update.

[ghisler(Author)]

Unfortunately you will get the same error (app not found) when trying to use "Add custom location" in Total Commander too. To access the card, Total Commander needs to get permission, which is provided by the "Files" app. This is a standard Android app which is unfortunately often missing on special devices like TVs and car units.

[tmihai20]

I think I tried it once as soon as I got my head unit and it did not work. The name of the missing app is com.android.documentsui and it is a system app, I cannot install it by any means. As I said, I hope the manufacturer will include a fix in the future. Thank you so much for replying

[ghisler(Author)]

Yes, com.android.documentsui is the internal name of the older "Files" app. The newer has the name com.google.android.documentsui.