Close #198: Add possibility to override the kernel commandline during boot (#217)

Usage example:
pmbootstrap flasher boot --cmdline "PMOS_NO_OUTPUT_REDIRECT"

Thanks, drebrez!

pmb/flasher/run.py

@@ -30,6 +30,9 @@ def run(args, action, flavor=None):
         raise RuntimeError("action " + action + " is not"
                            " configured for method " + method + "!")
 
+    _cmdline = args.deviceinfo["kernel_cmdline"]
+    if args.cmdline:
+        _cmdline = args.cmdline
     _base = args.deviceinfo["flash_offset_base"]
     if _base == "":
         _base = "0x10000000"
@@ -39,7 +42,7 @@ def run(args, action, flavor=None):
         "$BOOT": "/mnt/rootfs_" + args.device + "/boot",
         "$FLAVOR": flavor if flavor is not None else "",
         "$IMAGE": "/home/user/rootfs/" + args.device + ".img",
-        "$KERNEL_CMDLINE": args.deviceinfo["kernel_cmdline"],
+        "$KERNEL_CMDLINE": _cmdline,
         "$OFFSET_BASE": _base,
         "$OFFSET_KERNEL": args.deviceinfo["flash_offset_kernel"],
         "$OFFSET_RAMDISK": args.deviceinfo["flash_offset_ramdisk"],

pmb/parse/arguments.py

@@ -35,6 +35,7 @@ def arguments_flasher(subparser):
 
     # Boot, flash kernel, export
     boot = sub.add_parser("boot", help="boot a kernel once")
+    boot.add_argument("--cmdline", help="override kernel commandline")
     flash_kernel = sub.add_parser("flash_kernel", help="flash a kernel")
     export = sub.add_parser("export", help="create convenience symlinks to the"
                                            " generated image files (system,"