You can flash it back, but you need to adjust the Product ID, in order to be able to flash the SSA+ firmware. Basically you do the opposite cross-conversion, from a SVA1032 to the SSA3021+. The steps are the same, but the other way around.
There is no reason to do so: your warranty is voided anyway, as there will be remanescent information that points to the conversion having been made at some point and in SSA mode you have exactly the same functionality as with a SSA+ model.
If you are really paranoid about this, you could do a backup of the complete flash and then, when you want to restore the original state, you could flash the backup back. Correct me, if I am wrong, but this, however, is not totally free from risk, as the flashing routine might encounter a fault in your flash IC, preventing the completition of the flashing and rendering you with a brick.
Finally, there seems to be the possibility to restore a bricked device by means of a special recovery USB image. This is not public, though.
Summed up: get the SSA3021+, do the crossflash and generate keys for all options. Sit back and enjoy.