Restore stock rom from diff rom

[kernzy83]

Just wanted to see if this was normal. I'm relatively new to the ROM and rooting world so bare with me.

I installed safestrap recovery before switching roms, made a backup of stock rom, booted new rom with "safe system: Enabled". After doing that I had the new rom up and running just fine. Today I tried to restore the new rom by wiping dalvik and restoring to the stock rom. While doing this I got the "MD5 mismatch error" (after turning safe system off), when I got the error I just rebooted without turning safe system on. But it rebooted into the stock rom, I went back, turned safe system on and it booted into the new rom.

That normal or did I mess up the original rom install?