RGB LED Matrix Panel Drive Board For Raspberry Pi

Bought two recently together with their P4 64×64 matrices. I got them to work on a Pi4B with the hzeller library, BUT: For driving 64×64 matrices, this boards/shield requires soldering: You need to connect P4 to GND and P8 zu #E. Either solder two small wires or jumpers like I did (see pictures: before/after). This would be easier if the board already came with jumpers in the right place. I found the tip here: https://w2.electrodragon.com/Board-dat/MPC/MPC1073-DAT/MPC1073-test-log-dat/MPC1073-test-log-dat.md#more-demos However, contrary to what it says there, –led-multiplexing=0 (instead of 1) did the trick so this demo worked after soldering: sudo examples-api-use/demo –led-rows=64 –led-cols=64 –led-multiplexing=0 However, I get quite a bit of ghosting/artefacts when displaying small images and animations on a chain of just 2 64×64 matrices, even after tweaking with things like –led-pwm-lsb-nanoseconds 50 and –led-limit-refresh=240. Thus, driving two 64×64 matrices already seems to be the limit of what the hzeller library and a Pi4B can do, because of the many address lines that 64 x 64 matrices have.