in this section of code:
"Coming here, we know the cpu has one TLB mapping in TLB1 which maps 0xfffff000-0xffffffff one-to-one. We set up a second mapping that maps addr 1:1 for 64M, and then we jump to addr"
does it look like it's setting up entry 0 in TLB1 for the 1:1 mapping? But isn't entry 0 in TLB1 already used for the 4KB boot page (0xfffff000-0xffffffff)?