Вроде выяснил откуда 0x60: Execution Region RW_IRAM1 (Base: 0x40000000, Size: 0x000004e8, Max: 0x00010000, ABSOLUTE)
Base Addr Size Type Attr Idx E Section Name Object
0x40000000 0x00000060 Zero RW 41 .bss libspace.o(c_t.l)
0x40000060 0x00000000 Zero RW 2 HEAP startup.o
0x40000060 0x00000488 Zero RW 1 STACK startup.o