GDB Error on OS X: Remote target does not support flash erase

[valeros]

Hi!
The latest simavr from the master branch is not able to execute load command from GDB on MacOS:

simavr -g -m atmega328p -f 16000000

avr-gdb  /path/to/firmware.elf -ex "target remote :1234" -ex "load"

The same commands work just fine on Ubuntu 18.04

[msquirogac]

@buserror
To fix this properly, support for the following gdb packets must be added

1. vFlashErase
2. vFlashWrite
3. vFlashDone

I already got support for the first and last, yet the second one is a bit more challenging.

As documentation says, vFlashWrite uses the binary encoding mode like the X packet instead of the hex mode that most of the packets use.

1. Do you have already have a decoder for said mode? No problem if you don't, just wanted to be sure to avoid repeating code.
2. Unlike the M packet, vFlashWrite one doesn't have a length field and was thinking to add it as an argument of the gdb_handle_command function. Any problem with that?

[enekochan]

I was having the same problem and your fix worked for me, now I can load without problems. Don't know about the implications of what you said about vFlashWrite.

Are you planning on doing a PR with it? Thanks!

[buserror]

@msquirogac I think there is support for something like that in the self programing code -- ie the stuff the bootloader uses? not sure tho. Otherwise I coul dhave a look. And yes, as @enekochan mention, if you have a PR with what you already have... thanks!

[OzPineapple]

I have the same problem using the package from Arch repo. I'm using an Arch distro based

avr-gcc -mmcu=atmega8 -g -o test.elf test.S
simavr -m atmega8 -f 8000000 -g -v test.elf
avr-gdb test.elf -ex "target remote :1234" -ex "load"

So I get:

Reading symbols from test.elf...
Remote debugging using :1234
0x00000000 in __vectors ()
Remote target does not support flash erase

I do not understand if I need to do some extra config setup to make it work. May this also makes that the display comand shows nothing?

This the test.S file btw:

#include <avr/io.h>

.global main

main:
	ldi r16, 0x01
	ldi r17, 0x02
	add r16, r17
	ldi r17, 0xFF

[gatk555]

I found some time to try this yesterday and seem to have a working implementation of the three commands. But I do not understand what the use of it is. In the example above, "-ex load" is not necessary, as simavr has already loaded the file.
I suppose it could be convenient to re-compile and continue the same gdb session, but found that simavr enters an infinite loop after reset.