well I checked the CRC32 of Tosec with the one I bought from Vesalia and they are identical. I got strange problem with KS3.1 on two A500. The Amigas won't start on power-up unless something is connected to side-slot (like HDD controller: A590 or Alpha-power). BTW, it works flawlessly on A2000.
KS1.3 and KS2.04 work fine on A500.