If anyone has problems with stuck logo on boot, try this:
1. Remove the back cover of the SDS1102CML+ oscilloscope,
2, Remove the metal back of the cage
3. Connect RX,TX serial cables on the unpopulated J11 connector. Solder TX to the second pad and RX to the third pad.
4. Connect to serial: Baudrate 115200
5. Boot the oscilloscope, now you will see the boot log. If not, swap the RX,TX cables to your serial adaptor.
6. Unzip the contents of the P21R2.zip in a fat32 formated usb stick. Also unzip the SDS1000_arm.zip and copy the SDS1000_arm.app to the root of the usb flash drive.
7. Connect the usb flash drive to the oscilloscope and power off and the on the oscilloscope.
8. Let the oscilloscope to perform the FW Recovery.
9. Remove the usb flash drive and Reboot
10. done!
If the oscilloscope still hangs on the boot logo
Start the oscilloscope without the usb flash drive.
When the boot is complete, but still on logo
Insert the usb flash drive and type in the serial console:
mount /dev/sda1 /mnt
mount / -o remount,rw
cp /mnt/SDS1000_arm.app /usr/bin/siglent/SDS1000_arm.app
chmod +x /usr/bin/siglent/SDS1000_arm.app
mkdir -p /usr/bin/siglent/firmdata0/usr/log
cd /usr/bin/siglent/
./SDS1000_arm.app
Now the oscilloscope is back to life!
Please perform a hardware reset using the Math button method and you are good as new.
a big thanks to tv84 and tautech for their help!