Hello guys again! I have again tried to downgrade the boot. I'm so close to the solution but it still fails while trying to send the image through ttl.
![Frustrated :banghead:](https://www.omnimaga.org/Smileys/classic/banghead.gif)
Connecting the Rx and Tx is clear to me but the ground (GND), should I connect it to both GND pins in the calc or is 1 enough? Also when I'm trying to send the image, it just returns me random bytes with recognizable strings like "boot". Could you explain me the use of the ground cable and how should it exactly be connected? How about an example picture with all the connections made?
Info about my calc:
EDIT: Now after numerous tries when i click send the file, select boot2.img, xmodem and press send, it just says: "Not enough memory".... please help me!
For now I have tried more than 100 times, every time with different settings: many protocols (even straight binary), different bitrates and different boot images with different names and every time i have checked that the cables are well connected and there are no shortages but still no result...
It seems to be like a communication problem because most of the errors have been timeouts. If you know anything about the Rx and Tx lights in the TTL converter, please explain how should I understand their signification.
EDIT2: HELL YEAH I made it!
![w00t :w00t:](https://www.omnimaga.org/Smileys/classic/smiley_woot.gif)
The problem was in the USB/TTL interface but I changed to arduino uno and soldered some pins and it worked perfect. My next question: How do I downgrade because even I have boot2 version 3.10.16, the computer link doesn't allow me to install os 3.1.0 or anything below the version i had. I even tried tnocing the current 3.6.0.550 and then install it but straight after first boot the calc crashed and the os was automatically removed?
Situation now:
Only installable OS: 3.6.0.550 (not installed)
Boot2 version: 3.10.16