How to debug a raw binary with gdb - gdb

Question

I have a executable for an embedded device.
It does not have header information that gdb recognizes, but instead uses a proprietary header specified by the vendor.
I can analyse the file just fine using IDA-pro, but I'd like to run some code to see what it does.
The executable is loaded at address 0x52000000
However if I just load the file using
exec-file myfile
I get
"myfile": not in executable format: File format not recognized
And if I restore the memory at the correct location using:
restore myfile 52000000
I get:
You can't do that without a process to debug.
How do I get out of this chicken-and-egg problem?
I just want to jump in the middle of the code, set some registers to predetermined values and run some code to see what happens.
Note that I'm using the gdb ARM toolchain from ARM itself.

Answer 1

As per #artless_noise suggestion I did the following:
objcopy.exe
--output-target=elf32-bigarm
--input-target=binary
--change-start=0x52000000
INPUTFILE OUTPUTFILE
This adds an elf header to the file.
However it does not fix the whole problem.
The output of
readelf.exe -a OUTPUTFILE
gives:
ELF Header:
Magic: 7f 45 4c 46 01 02 01 61 00 00 00 00 00 00 00 00
Class: ELF32
Data: 2's complement, big endian
Version: 1 (current)
OS/ABI: ARM
ABI Version: 0
Type: REL (Relocatable file)
Machine: ARM
Version: 0x1
Entry point address: 0x52000000
Start of program headers: 0 (bytes into file)
Start of section headers: 57316 (bytes into file)
Flags: 0x0
Size of this header: 52 (bytes)
Size of program headers: 0 (bytes)
Number of program headers: 0
Size of section headers: 40 (bytes)
Number of section headers: 5
Section header string table index: 2
Section Headers:
[Nr] Name Type Addr Off Size ES Flg Lk Inf Al
[ 0] NULL 00000000 000000 000000 00 0 0 0
[ 1] .data PROGBITS 00000000 000034 00df8c 00 WA 0 0 1
.....
Note that the .data section still has an address of 0x00000000. This should be 0x52000000.
To fix this I opened up a hex editor at address 0xdf8c.
This is close the where the section headers are.
The structure of the section headers is as follows, along with the data I expect to be there.
typedef struct {
Elf32_Word sh_name;
Elf32_Word sh_type; = 1 {.data}
Elf32_Word sh_flags; = ?
Elf32_Addr sh_addr; = 0x00000000
Elf32_Off sh_offset; = 0x00000034
Elf32_Word sh_size; = 0x0000df8c
Elf32_Word sh_link;
Elf32_Word sh_info;
Elf32_Word sh_addralign;
Elf32_Word sh_entsize;
} Elf32_Shdr;
The first header is always all zeros, the second header is the .data section.
So I look for the magic numbers and fill in the starting address, save the file and reload it into gdb.
Now it works