Floating Point-enabled STM32

I spent the day on Rust Programming of a STM32F722 Nucleo Board. It all went right until I tried to compile with Floating Point enabled. (thumbv7em-none-eabihf)
The generated ELF File also looks OK, but I do not get managed to bring the file to a binary raw format in order to flash it to my system with the texane st-flash utility.
When I "arm-none-eabi-objcopy target/thumbv7em-none-eabihf/debug/stm32f7rust stm32f7rust.bin -O binary", the output is zero size. Im pretty sure that the ELF File is OK (at least more than zero size), because I "cargo readobj --bin stm32f7rust -- -file-headers" with the following result: UPSers

ELF Header:
Magic: 7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
Class: ELF32
Data: 2's complement, little endian
Version: 1 (current)
OS/ABI: UNIX - System V
ABI Version: 0x0
Type: EXEC (Executable file)
Machine: ARM
Version: 0x1
Entry point address: 0x0
Start of program headers: 52 (bytes into file)
Start of section headers: 985244 (bytes into file)
Flags: 0x5000400
Size of this header: 52 (bytes)
Size of program headers: 32 (bytes)
Number of program headers: 3
Size of section headers: 40 (bytes)
Number of section headers: 16
Section header string table index: 14

Can anyone give me a hint, whether it is (or not is) possible to generate a raw binary this way?

Thanks in advance.

I never encountered this problem, but this and this question on Stack Overflow suggest that your objcopy might be expecting different section names compared to what the compiler actually generates.