hi jvov and thank you for your reply.
I have already successfully tested (simulated) altpll along with altpll_reconfig. My problem is that altpll_reconfig uses some memory bits (144 I think) that the fitter implements as a whole M9K block (I use EP3C16Q249C8). Due to my design memory requirements I need to get rid of that extra memory block, so I m trying to avoid using altpll_reconfig if possible.
Now, because altpll uses a mif file during reconfiguration just like altpll_reconfig does, I thought maybe I could just use "Update Memory Initialization" option at the Quartus along with Assembler to update that mif file without having to run the whole compilation process. The thing is, that when I update mif files, only the one that initiates altpll_reconfig is updated and not that of the alt_pll. I must admit that the term "on the fly" doesn't really describe the function I want to achieve here.