I had problems to burn a bootloader to an Arduino 328P-AU (TQFP32) on my self made board. First I tried an USBasp which could not get a connection to the target. I checked all wiring around the 328-chip and found that there was no toggling on the osc pins.
After many vain trials I used an Arduino board with Arduino ISP sketch and this was successful. Now the osc pins of the 328P, TQFP, were toggling.
And after that also USBasp can load a bootloader or any sketch.
Reading a lot of postings in this forum I found a hint that some chips are configured internally to use the onboard oscillator. In such chips some fuses need to be burnt to use an external crystal or ceramic resonator. This is the only explanation I can find why initially USBasp failed to burn a bootloader.
Are there further/better explanations and is there a better firmware for USBasp which can burn a bootloader on a new 328P-AU chip?