You might be able to Ball Grid Array solder a compatible Intel System on Chip of the same generation (look into the Bay Trail Celeron/Pentium N series) with more cache or cores, or upgrade RAM if it isn’t soldered down. (NOTE: HP and probably other manufacturers have been utilizing early boot security to lock people to their parts only) Also note that the power delivery might only be able to handle your system on chip’s power usage, others may draw more power.
Xeons and most of the Core series use different sockets.