Disable reset on DTR but retaining avrdude compatibility?

The 120ohm resistor did not work reliably so I disabled DTR reset by cutting the cap out.

In my user code I am detecting first STK500 command coming from avrdude and responding to it, but then would like to to jump to bootloader without 4ms or 65ms power on delay after WDT reset, and have bootloader to immediately take over and without customizing the bootloader this seems like a showstopper.

Secondly, in the near future will need some way to replace firmware by user via web interface so if I end up having to replace bootloader I am thinking making file on SD where first few sectors will have list of remaining sectors of the file, so bootloader can simply load file from SD without any knowledge of file system. I believe this is how Linux Bootloader LILO worked, but I may be wrong.

Anyone has done something like this ?

Btw. perhaps this topic should be in Project Guidance forum ... did not realize until I posted it.

I wonder why my posts are being ignored on this forum.

To follow up, customer decided to get rid of Arduino as main controller. Will finish basic functionality prototypes with MEGAs. Main issues are W5100 has only 4 sockets, web interface often does not load and we had to do serializing CSS/JS loading in the user interface. Webserver is only able to output 50kB/s so operating via browser is the pain (don't look at me, I did not select Arduino for this large aeroponics project in the first place).

I am currently deciding between Odroid C1 and Beaglebone Black and Nano's for remote I/Os via RS485. We want to put Nano everywhere, in every pipe where anything can be measured or controlled.

Liking OC1 speed of Pentium 3 on credit card size and 4 USBs, btw for some reason linux image comes with avr-gcc and avrdude out of the box, and you can apt-get Arduino IDE as well. It looks funny when flashing Arduino MEGA from OC1 because it's larger. Lighttpd was able to output 80MB/sec so network is a strong point of OC1.

OTOH BB has way more I/Os on the base board and I like the idea of 2 dedicated 200MHz cores available solely to real-time use. Price is little higher than OC1 but has 4GB eMMC included, very fast and more than enough.

dipmicro:
I wonder why my posts are being ignored on this forum.

Asking impossible questions may not help?

dipmicro:
The 120ohm resistor did not work reliably so I disabled DTR reset by cutting the cap out.

Right!

Paul__B:
Asking impossible questions may not help?

Concept is solid - user code receives STK500 command 1B 01 00 01 0E 01 14, responds with 1B 01 00 0B 0E 01 00 08 41 56 52 49 53 50 5F 32 74, flush, disable interrupts, long jump to specific service in bootloader, who continues in conversation with avrdude. Maybe someone has done this differently, but this is how I was going to make it work. It's irrelevant now. What is impossible question?