How to add new folder under boot folder

is there someone who knows how to create a new folder under ‘/’ ?
Hikey960 rootfs is read-only, I want to copy one shared c-lib to /lib folder.
but I try to mkdir /lib in out/target/product/hikey960/system, it doesn’t work.

You can have mount partition information with the mount command. / and /system are read-only. You can remount /system to rw at runtime via adb:
$ adb root
$ adb remount

To add your lib at buildtime, You can create your own prebuilt Android ‘module’ with a proper Android Makefile, but I suggest you to modify your device makefile (device/linaro/hikey/hikey960/ and add your copy rule to PRODUCT_COPY_FILES.

PRODUCT_COPY_FILES += device/linaro/hikey/

hi, Loic
thanks, I did following commands:
adb root
adb remount
but boot folder “/” is still read-only mode. I need to add lib folder just under boot folder, /lib/my.lib.
because the sharing lib of object executable file is to /lib folder:

ELF executable, 64-bit LSB arm64, dynamic (/lib/, BuildID=90fe6da411d0e449bcd5e4df76b2666e4f79ab97, not stripped

Are you trying to use a glibc linux binary on Android ? your binary points to which is known as the ELF Interpreter. /lib/ is typically the glibc linux elf interpreter. Android has it own ELF interpreter (/system/bin/linker64) and libc (bionic).

ELF executables contain path to the ELF interpreter which is used to ‘start’ themself. To keep it simple, you have to (cross-)compile your app for Android target so that your executable use the correct elf-interpreter/libc, is it something you considered?

hi, Loic
do you ever use sg3-utils in the android system? I tried to use “android/prebuilts/gcc/linux-x86/aarch64/aarch64-linux-android-4.9” to compile it, but compiling failed. then I switched cross-compiler to this one, it passed, and but it came to the result as you said above.
if you have good cross-compile for Android target, can you tell me download link?

You are going to have to modify the source code of what you are trying to compile such that it becomes compatible with bionic.