“We implement these patterns in our Rowhammer fuzzer named Blacksmith and show that it can bypass TRR on 100% of the PC-DDR4 DRAM devices in our test pool.”
Memory makers answered Rowhammer with Target Row Refresh and told everyone the problem was handled. ETH Zurich hammered rows unevenly instead of in lockstep and broke every DDR4 module they tested. You cannot patch a DRAM chip. Every one of those sticks stays vulnerable until it is thrown away.