Cannot authorize CJ on legacy fw - Hard fault detected

[marekrjpolak]

Describe the bug
When trying to authorize CJ on legacy fw built from current main (both locally or in GH action), device shows Hard fault detected. Please unplug the device. On 1.12.1 or locally built firmware approximately from that time (March 2023) it works as expected.

I was testing it in desktop Suite with regtest and local coordinator.

[onvej-sl]

I discovered that this bug

• was introduced in a0aa414,
• doesn't only concern coinjoin, tests/device_tests/bitcoin/test_multisig.py, for example, causes the hard fault as well.

[onvej-sl]

New discoveries:

• The hard fault happens on this line.
• It is caused by updating gcc-arm-embedded from 10.3.1 to 12.2.1.
• Updating gcc-arm-embedded to 12.3.1 or to 13.2.1 didn't help.
• Updating nanopb to 0.4.8 didn't help.