I have two indetical routers
https://mikrotik.com/product/RB2011UiAS-2HnD-IN
One of them when booting write
RouterBOOT booter 3.41
RouterBoard 2011UiAS-2HnD
CPU frequency: 600 MHz
Memory speed: 200 MHz
Memory size: 128 MiB
NAND size: 128 MiB
another write
RouterBOOT booter 3.41
RouterBoard 2011UiAS-2HnD r2
CPU frequency: 600 MHz
Memory speed: 200 MHz
Memory size: 128 MiB
NAND size: 128 MiB
What different between them?