pmb.flasher: Improve flash_lk2nd action

* Check that we're not already running lk2nd as flashing boot partition
  inside lk2nd is different to flashing boot partition outside. We could
  improve this in the future to use "flash lk2nd lk2nd.img" as
  documented in the file.
* Grab the lk2nd package from the device package and install that. The
  device package is expected to have a dependency on the correct lk2nd
  package.
* Remove some log message in unusual styles for pmbootstrap.
* Group flash_lk2nd action together with the other flash actions and use
  string comparison.

See also: https://gitlab.com/postmarketOS/pmaports/-/issues/2074



Reviewed-by: Oliver Smith <ollieparanoid@postmarketos.org>
Link: https://lists.sr.ht/~postmarketos/pmbootstrap-devel/%3C20230605104026.744005-1-luca@z3ntu.xyz%3E

pmb/flasher/frontend.py

@@ -110,15 +110,38 @@ def sideload(args):
 
 
 def flash_lk2nd(args):
-    chroot_path = args.work + "/chroot_rootfs_" + args.device
-    lk2nd_path = "/boot/lk2nd.img"
-    if not os.path.exists(chroot_path + lk2nd_path):
-        raise RuntimeError(f"{chroot_path+lk2nd_path} doesn't exist. Your"
-                           " device may not support lk2nd.")
-
-    logging.info(lk2nd_path)
-    logging.info("It's normal if fastboot warns"
-                 " \"Image not signed or corrupt\" or a similar warning")
+    method = args.flash_method or args.deviceinfo["flash_method"]
+    if method == "fastboot":
+        # In the future this could be expanded to use "fastboot flash lk2nd $img"
+        # which reflashes/updates lk2nd from itself. For now let the user handle this
+        # manually since supporting the codepath with heimdall requires more effort.
+        pmb.flasher.init(args)
+        logging.info("(native) checking current fastboot product")
+        output = pmb.chroot.root(args, ["fastboot", "getvar", "product"],
+                                 output="interactive", output_return=True)
+        # Variable "product" is e.g. "LK2ND_MSM8974" or "lk2nd-msm8226" depending
+        # on the lk2nd version.
+        if "lk2nd" in output.lower():
+            raise RuntimeError("You are currently running lk2nd. Please reboot into the regular"
+                               " bootloader mode to re-flash lk2nd.")
+
+    # Get the lk2nd package (which is a dependency of the device package)
+    device_pkg = f"device-{args.device}"
+    apkbuild = pmb.helpers.pmaports.get(args, device_pkg)
+    lk2nd_pkg = None
+    for dep in apkbuild["depends"]:
+        if dep.startswith("lk2nd"):
+            lk2nd_pkg = dep
+            break
+
+    if not lk2nd_pkg:
+        raise RuntimeError(f"{device_pkg} does not depend on any lk2nd package")
+
+    # Install device package since that should also install lk2nd package
+    suffix = "rootfs_" + args.device
+    pmb.chroot.apk.install(args, [lk2nd_pkg], suffix)
+
+    logging.info("(native) flash lk2nd image")
     pmb.flasher.run(args, "flash_lk2nd")
 
 
@@ -143,11 +166,11 @@ def frontend(args):
         flash_vbmeta(args)
     elif action == "flash_dtbo":
         flash_dtbo(args)
+    elif action == "flash_lk2nd":
+        flash_lk2nd(args)
     elif action == "list_flavors":
         list_flavors(args)
     elif action == "list_devices":
         list_devices(args)
     elif action == "sideload":
         sideload(args)
-    elif action in ["flash_lk2nd"]:
-        flash_lk2nd(args)