Many <unknown>s in objdump


when I try to get an object dump from a rust binary for the attiny85 microcontroller, many instructions and/or addresses are unknown:

cargo objdump --target avr-attiny85.json --bin rust-attiny85-missing-interrupt --color auto --release -- --disassemble --no-show-raw-insn --print-imm-hex

The result is:

    Finished release [optimized + debuginfo] target(s) in 0.04s

rust-attiny85-missing-interrupt.elf:	file format elf32-avr

Disassembly of section .text:

00000000 <__vectors>:
       0: 0e c0        	rjmp	<unknown>
       2: 28 c0        	rjmp	<unknown>
       4: 40 c0        	rjmp	<unknown>
       6: 26 c0        	rjmp	<unknown>
       8: 25 c0        	rjmp	<unknown>
       a: 24 c0        	rjmp	<unknown>
       c: 23 c0        	rjmp	<unknown>
       e: 22 c0        	rjmp	<unknown>
      10: 21 c0        	rjmp	<unknown>
      12: 20 c0        	rjmp	<unknown>
      14: 1f c0        	rjmp	<unknown>
      16: 1e c0        	rjmp	<unknown>
      18: 1d c0        	rjmp	<unknown>
      1a: 1c c0        	rjmp	<unknown>
      1c: 34 c0        	rjmp	<unknown>

0000001e <__trampolines_start>:
      1e: 11 24        	clr	r1
      20: 1f be        	out	0x3f, r1
      22: cf e5        	ldi	r28, 0x5f
      24: d2 e0        	ldi	r29, 0x2
      26: de bf        	out	0x3e, r29
      28: cd bf        	out	0x3d, r28


00000056 <main>:
      56: ef 92 ff 92  	<unknown>
      5a: 0f 93 1f 93  	<unknown>
      5e: cf 93 df 93  	<unknown>
      62: cd b7        	in	r28, 0x3d
      64: de b7        	in	r29, 0x3e
      66: 21 97 0f b6  	<unknown>
      6a: f8 94        	cli
      6c: de bf        	out	0x3e, r29
      6e: 0f be        	out	0x3f, r0
      70: cd bf        	out	0x3d, r28
      72: 8e 01 0f 5f  	<unknown>
      76: 1f 4f        	sbci	r17, 0xff
      78: 88 ee        	ldi	r24, 0xe8
      7a: 93 e0        	ldi	r25, 0x3
      7c: 7c 01 c8 01  	<unknown>
      80: b7 01 12 d0  	<unknown>
      84: fc cf        	rjmp	<unknown>

You can see the code that generated this in this post:

What can I do to improve that?


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