Some Mediatek devices have a special 512-byte header around the zImage
which must be generated so the device boots.
Support for that exists for a while in postmarketOS but detection was
missing. Add that.
While at it, also remove unnecessary "#!/usr/bin/env python3" in files
that only get imported, and adjust other empty/comment lines in the
beginnings of the files for consistency.
This makes files easier to read, and makes the pmbootstrap codebase more
consistent with the build.postmarketos.org codebase.
Replace the "Add topdir to import path" boilerplate lines in each test
file with a simple "import pmb_test". Use the "# noqa" comment if
"pmb_test" is not used further in the test file, so flake8 does not
complain about an unused module.
Make the path to the testdata available as pmb_test.const.testdata, and
use pmb.config.pmb_src to access the topdir in all tests.
This is in preparation for new "pmbootstrap status" related tests, which
will have shared test code in test/pmb_test/. Also, this makes the
pmbootstrap codebase more consistent with the bpo codebase, which has a
similar "import bpo_test" mechanism.
postmarketOS/pmaports!700 adds a new "deviceinfo_bootimg_dtb_second"
option that places the DTB in the "second" area of the Android boot
image.
Attempt to detect this automatically by checking the extracted
second binary for the FDT magic (0xd00dfeed).
We are analyzing the `boot.img` with `file` before we send it to
`unpackbootimg`. File does not recognize all kinds of `boot.img` files,
which `unpackbootimg` can extract, so we need a way to skip this check.
Details:
* Add `-f` parameter, continues extraction with a warning if the file
seems to be invalid
* Tell the user that `-f` can be used if the `boot.img` is invalid and
it's not specified
* Consistent spelling of `boot.img` instead of `bootimg` in messages
Fixes#1608
