@IrfanLatif Wow you're right, I don't understand how I could overlook it. Can you repost your reply as an answer?

@IrfanLatif On Nokia 8, no root, it returns "-r-xr-xr-x 1 shell shell u:object_r:shell_data_file:s0 138 2020-04-30 22:50 /data/local/tmp/printf" for the first command and "/data/local/tmp/printf: ELF executable, 32-bit LSB arm, static, stripped" for the second one.

@alecxs Why do you think my executable is broken? It runs just fine on an armv7 device. Perhaps you misunderstand my question, I'm not interested in printf functionality. I named my executable "printf" just because it prints something to stdout.

@alecxs Can you be more specific please? When I rename my printf executable to printfx and run ./busybox-armv8l printfx from /data/local/tmp/, it says "printfx: applet not found" because it expects the parameter to be one of the functions supported by busybox.