simavr ignores memory content of located sections - gdb

Question

Question also posted in https://github.com/buserror/simavr/issues/484
For a project with an Atmega324P I use special sections to ensure that some code is located on desired addresses. Works fine on real target, but these sections are not loaded proper in simavr.
Any idea what is going wrong and how to solve this problem?
To reproduce this problem I use an Ubuntu system with avr-gcc (5.4.0), avr-gdb (10.1.90.20210103-git) and simavr (1.6+dfsg-3).
Create file main.c
#define ATT_SECTION_APP __attribute__((section(".app")))
int main () ATT_SECTION_APP;
int main () {
asm("nop");
return 0;
}
Build project and locate section .app to 0x7100
avr-gcc -c -o main.o main.c
avr-gcc -o main.elf -Wl,-section-start=.app=0x7100 -mmcu=atmega324p main.o
Check result in elf-file
Disassemble elf-file with avr-objdump -d main.elf
Disassembly of section .app:
00007100 <main>:
7100: cf 93 push r28
7102: df 93 push r29
7104: cd b7 in r28, 0x3d ; 61
7106: de b7 in r29, 0x3e ; 62
7108: 00 00 nop
710a: 80 e0 ldi r24, 0x00 ; 0
710c: 90 e0 ldi r25, 0x00 ; 0
710e: df 91 pop r29
7110: cf 91 pop r28
7112: 08 95 ret
Start simavr
simavr -g -m atmega324p main.elf
Start avr-gdb and show memory on location 0x7100
Start in another shell avr-gdb with avr-gdb main.elf.
Then execute the following commands on gdb console:
target remote localhost:1234
x/20b 0x7100
As you can see, the memory locations starting with 0x7100 are cleared (= 0xff) instead of showing the same content as in disassembly view. Symbols like main are shown as desired.
(gdb) target remote localhost:1234
Remote debugging using localhost:1234
0x00000000 in __vectors ()
(gdb) x/20b 0x7100
0x7100 <main>: 0xff 0xff 0xff 0xff 0xff 0xff 0xff 0xff
0x7108 <main+8>: 0xff 0xff 0xff 0xff 0xff 0xff 0xff 0xff
0x7110 <main+16>: 0xff 0xff 0xff 0xff