Hi, I have an unofficial Arduino uno that won't execute new programs. I put a clock program in it then when I wanted to upload another program into it it wouldn't do it. It would keep doing the clock thing. I have a data logger shield and an LCD display that has some buttons connected to it but when I take it off it spams the Monitor with couldn't find RCT (i coded it to do that). Pls any help would be appreciated 
Welcome to the forum
Start simple. Remove everything connected to the Arduino except the USB lead, do File/New and upload the blank sketch. What messages do you get in the output window ?
- Have you got the correct board type selected ?
- Is the COM port created when you plug in the board ?
- Have you got the correct COM port selected ?
- Have you tried a different USB lead ?
- Are you sure that the USB lead is a data cable and not a charging cable ?
Well here are the answers
The only message that I get is the message that I programmed it to say when I don't have the shield on it Couldn't find RTC and I did upload a blank sketch to it.
- Yes
- Yes
- Yes
- Yes
- Yes (the USB lead came in a kit)
and i am also on Arduino Cloud
Does the built in IDE example blink sketch work correctly on your board?
Nope, still executing the old program
Ok. From memory, can you click on File-> Preferences and select verbose output on compilation, and also upload.
If you recompile the blink sketch and upload it to your UNO, then select all the text in the lower window in the IDE and copy it into a new post here.
It's explained a bit better here:
I know I am repeating this but I am on the web editor so I think I have verbose output always on at the bottom but here is a video and the output
link to the video: A video.mp4 - Google Drive
The output:
/usr/local/bin/arduino-cli compile --fqbn arduino:avr:uno --libraries /home/builder/opt/libraries/latest --build-cache-path /tmp --output-dir /tmp/841515002/build --build-path /tmp/arduino-build-8A9FC410B7BF42A1DF470C83208286AF -v /tmp/841515002/Blink_copy
Using board 'uno' from platform in folder: /home/builder/.arduino15/packages/arduino/hardware/avr/1.8.4
Using core 'arduino' from platform in folder: /home/builder/.arduino15/packages/arduino/hardware/avr/1.8.4
Detecting libraries used...
/home/builder/.arduino15/packages/arduino/tools/avr-gcc/7.3.0-atmel3.6.1-arduino7/bin/avr-g++ -c -g -Os -w -std=gnu++11 -fpermissive -fno-exceptions -ffunction-sections -fdata-sections -fno-threadsafe-statics -Wno-error=narrowing -flto -w -x c++ -E -CC -mmcu=atmega328p -DF_CPU=16000000L -DARDUINO=10607 -DARDUINO_AVR_UNO -DARDUINO_ARCH_AVR -I/home/builder/.arduino15/packages/arduino/hardware/avr/1.8.4/cores/arduino -I/home/builder/.arduino15/packages/arduino/hardware/avr/1.8.4/variants/standard /tmp/arduino-build-8A9FC410B7BF42A1DF470C83208286AF/sketch/Blink_copy.ino.cpp -o /dev/null
Generating function prototypes...
/home/builder/.arduino15/packages/arduino/tools/avr-gcc/7.3.0-atmel3.6.1-arduino7/bin/avr-g++ -c -g -Os -w -std=gnu++11 -fpermissive -fno-exceptions -ffunction-sections -fdata-sections -fno-threadsafe-statics -Wno-error=narrowing -flto -w -x c++ -E -CC -mmcu=atmega328p -DF_CPU=16000000L -DARDUINO=10607 -DARDUINO_AVR_UNO -DARDUINO_ARCH_AVR -I/home/builder/.arduino15/packages/arduino/hardware/avr/1.8.4/cores/arduino -I/home/builder/.arduino15/packages/arduino/hardware/avr/1.8.4/variants/standard /tmp/arduino-build-8A9FC410B7BF42A1DF470C83208286AF/sketch/Blink_copy.ino.cpp -o /tmp/arduino-build-8A9FC410B7BF42A1DF470C83208286AF/preproc/ctags_target_for_gcc_minus_e.cpp
/home/builder/.arduino15/packages/builtin/tools/ctags/5.8-arduino11/ctags -u --language-force=c++ -f - --c++-kinds=svpf --fields=KSTtzns --line-directives /tmp/arduino-build-8A9FC410B7BF42A1DF470C83208286AF/preproc/ctags_target_for_gcc_minus_e.cpp
Compiling sketch...
/home/builder/.arduino15/packages/arduino/tools/avr-gcc/7.3.0-atmel3.6.1-arduino7/bin/avr-g++ -c -g -Os -w -std=gnu++11 -fpermissive -fno-exceptions -ffunction-sections -fdata-sections -fno-threadsafe-statics -Wno-error=narrowing -MMD -flto -mmcu=atmega328p -DF_CPU=16000000L -DARDUINO=10607 -DARDUINO_AVR_UNO -DARDUINO_ARCH_AVR -I/home/builder/.arduino15/packages/arduino/hardware/avr/1.8.4/cores/arduino -I/home/builder/.arduino15/packages/arduino/hardware/avr/1.8.4/variants/standard /tmp/arduino-build-8A9FC410B7BF42A1DF470C83208286AF/sketch/Blink_copy.ino.cpp -o /tmp/arduino-build-8A9FC410B7BF42A1DF470C83208286AF/sketch/Blink_copy.ino.cpp.o
Compiling libraries...
Compiling core...
Using precompiled core: /tmp/core/core_arduino_avr_uno_f1d675a35cb302d87396e400c56d2f7e.a
Linking everything together...
/home/builder/.arduino15/packages/arduino/tools/avr-gcc/7.3.0-atmel3.6.1-arduino7/bin/avr-gcc -w -Os -g -flto -fuse-linker-plugin -Wl,--gc-sections -mmcu=atmega328p -o /tmp/arduino-build-8A9FC410B7BF42A1DF470C83208286AF/Blink_copy.ino.elf /tmp/arduino-build-8A9FC410B7BF42A1DF470C83208286AF/sketch/Blink_copy.ino.cpp.o /tmp/arduino-build-8A9FC410B7BF42A1DF470C83208286AF/../core/core_arduino_avr_uno_f1d675a35cb302d87396e400c56d2f7e.a -L/tmp/arduino-build-8A9FC410B7BF42A1DF470C83208286AF -lm
/home/builder/.arduino15/packages/arduino/tools/avr-gcc/7.3.0-atmel3.6.1-arduino7/bin/avr-objcopy -O ihex -j .eeprom --set-section-flags=.eeprom=alloc,load --no-change-warnings --change-section-lma .eeprom=0 /tmp/arduino-build-8A9FC410B7BF42A1DF470C83208286AF/Blink_copy.ino.elf /tmp/arduino-build-8A9FC410B7BF42A1DF470C83208286AF/Blink_copy.ino.eep
/home/builder/.arduino15/packages/arduino/tools/avr-gcc/7.3.0-atmel3.6.1-arduino7/bin/avr-objcopy -O ihex -R .eeprom /tmp/arduino-build-8A9FC410B7BF42A1DF470C83208286AF/Blink_copy.ino.elf /tmp/arduino-build-8A9FC410B7BF42A1DF470C83208286AF/Blink_copy.ino.hex
/home/builder/.arduino15/packages/arduino/tools/avr-gcc/7.3.0-atmel3.6.1-arduino7/bin/avr-size -A /tmp/arduino-build-8A9FC410B7BF42A1DF470C83208286AF/Blink_copy.ino.elf
Sketch uses 1878 bytes (5%) of program storage space. Maximum is 32256 bytes.
Global variables use 194 bytes (9%) of dynamic memory, leaving 1854 bytes for local variables. Maximum is 2048 bytes.
Upload started
Programming with: avrgirl-arduino flash -f undefined -a uno -p /dev/ttyACM0
connected
reset complete.
flashing, please wait...
flash complete.
I don't see any errors in the output.
It looks like the sketch is compiled and successfully uploaded to the board.
What is the result? The board still execute old program ?
yes
Please answer in more detail
did you remove all the added parts (lcd, rtc, etc) and then try to upload blink?
Do you try to upload new sketch with PC-based (non-web) version of IDE?
I think you might be onto something. Here is the verbose output.
Arduino: 1.8.19 (Windows Store 1.8.57.0) (Windows 10), Board: "Arduino Uno"
Sketch uses 924 bytes (2%) of program storage space. Maximum is 32256 bytes.
Global variables use 9 bytes (0%) of dynamic memory, leaving 2039 bytes for local variables. Maximum is 2048 bytes.
An error occurred while uploading the sketch
avrdude: verification error, first mismatch at byte 0x0002
0x63 != 0x5c
avrdude: verification error; content mismatch
This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.
When i've seen a verification error, it usually turns out to be a failure in the flash memory of the 328P.
I've never used the web editor setup. I wonder why that reported back "flash complete" when potentially it failed?
This is the Arduino editor from the Microsoft store as it says here:
Arduino: 1.8.19 (Windows Store 1.8.57.0) (Windows 10), Board: "Arduino Uno"
Hi guys today i found out the problem. I broke my bootloader so I got to burn some mew code onto it