"To be honest, even with this flash, who can promise even this release is fault proof."
As you can read here, people found out, that the fix mostly has something to do with the fact, that Glinet used wrong/too high current values for the emmc, maybe in the hope to boost its write speed, idk? If this is true, only Glinet can confirm, I would expect that the current value is mostly both stored in the uboot and also in the firmware, both seperated. I would interpretate it, that if you just flash fw, the too high current is solved every boot and mostly no problem will happen over time. But if it stays in uboot, I would expect, that with every fw flash, there is a chance the device bricks (mostly fries the emmc). So it is a very very very very important thing to both flash fw and uboot. Or if you never will update fw in the future, you dont need to.