Что за магическая комбинация '1,,L' ?

INPUT FORMAT
sfdisk reads lines of the form
<start> <size> <id> <bootable> <c,h,s> <c,h,s>
where each line fills one partition descriptor.

Fields are separated by whitespace, or comma or semicolon possibly followed by whitespace; initial and trailing white&#8208;
space is ignored. Numbers can be octal, decimal or hexadecimal, decimal is default. When a field is absent or empty,
a default value is used.

The <c,h,s> parts can (and probably should) be omitted - sfdisk computes them from <start> and <size> and the disk
geometry as given by the kernel or specified using the -H, -S, -C flags.

Bootable is specified as [*|-], with as default not-bootable. (The value of this field is irrelevant for Linux - when
Linux runs it has been booted already - but might play a role for certain boot loaders and for other operating systems.
For example, when there are several primary DOS partitions, DOS assigns C: to the first among these that is bootable.)

Id is given in hex, without the 0x prefix, or is [E|S|L|X], where L (LINUX_NATIVE (83)) is the default, S is LINUX_SWAP
(82), E is EXTENDED_PARTITION (5), and X is LINUX_EXTENDED (85).

версия sfdisk 2.27.2

В fdisk отступ оказался 2048, но это не помешало плате загрузиться.