What are the extra image files that are automatically added after build?

[zhiyong-ft]

Hi,

I am trying to integrate MCUBoot into our project, and noticed that some extra image files are automatically generated after build. After compiling a demo for mbed-os, the following two extra images are automatically generated:

//* is the project folder name
*_application.hex
*_update.bin
// The following is the expected image file
*.hex

The expected image file seems work just fine, but I am curious what the other two are for. Mbed can run python scripts postbuild per target, but I don't see any relevant scripts and never noticed such extra image files when working with other projects for the same target. So I am wondering if those two extra image files are generated by some script in mcuboot project.

The full console output from Mbed Studio is included below:

Building project MCUBoot-Bootloader (NUCLEO_F429ZI, ARMC6)
Scan: MCUBoot-Bootloader
Using ROM regions application, post_application in this build.
Region application: size 0xc000, offset 0x8000000
Region post_application: size 0x1f4000, offset 0x800c000
Link: MCUBoot-Bootloader
[Warning] @0,0: L3912W: Option 'legacyalign' is deprecated.
Elf2Bin: MCUBoot-Bootloader
Merging Regions
Filling region application with BUILD/NUCLEO_F429ZI/ARMC6\MCUBoot-Bootloader_application.hex
Space used after regions merged: 0x7f78
Merging Regions
Filling region application with BUILD/NUCLEO_F429ZI/ARMC6\MCUBoot-Bootloader_application.hex
Space used after regions merged: 0x7f78
| Module               |     .text |   .data |      .bss |
|----------------------|-----------|---------|-----------|
| [lib]\mc_w.l         |   940(+0) |  12(+0) |    40(+0) |
| anon$$obj.o          |    32(+0) |   0(+0) |  4352(+0) |
| default_bd.o         |    64(+0) |   0(+0) |    48(+0) |
| mbed-os\connectivity |  8268(+0) |   0(+0) |     0(+0) |
| mbed-os\drivers      |   892(+0) |   0(+0) |     8(+0) |
| mbed-os\hal          |   722(+0) |   4(+0) |    58(+0) |
| mbed-os\platform     |  5527(+0) | 132(+0) |   222(+0) |
| mbed-os\storage      |  1080(+0) |   0(+0) |     0(+0) |
| mbed-os\targets      |  6384(+0) |  12(+0) |   164(+0) |
| mcuboot\boot         |  8231(+0) |   4(+0) | 10760(+0) |
| signing_keys.o       |   274(+0) |   0(+0) |     0(+0) |
| Subtotals            | 32414(+0) | 164(+0) | 15652(+0) |
Total Static RAM memory (data + bss): 15816(+0) bytes
Total Flash memory (text + data): 32578(+0) bytes
Update Image: BUILD/NUCLEO_F429ZI/ARMC6\MCUBoot-Bootloader_update.bin
Image: BUILD/NUCLEO_F429ZI/ARMC6\MCUBoot-Bootloader.hex

Thanks,
ZL