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Windows Iot Image Helper 16


Before launching the image helper app, make sure the microSD card being used for the Pi is read/write accessible to the laptop or desktop app host system. Then, start the Windows IoT Core Image Helper app. Once started, select the correct SD card. As for the required .ffu file that is located under the application folder in the FFU directory. Confirm the correct SD card is selected and the ffu file is identified then click Flash button. Flash will spawn a command dialog that provides percentage completion output. Once finished, a notification pops up with overall status. If successful then remove the microSD from the app host system and insert into Pi. Make sure all Pi hardware is good-to-go (monitor, power, mouse, keyboard), then power on the Pi.




windows iot image helper 16


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This specification describes the structure of executable (image) files and object files under the Windows family of operating systems. These files are referred to as Portable Executable (PE) and Common Object File Format (COFF) files, respectively.


This document specifies the structure of executable (image) files and object files under the Microsoft Windows family of operating systems. These files are referred to as Portable Executable (PE) and Common Object File Format (COFF) files, respectively. The name "Portable Executable" refers to the fact that the format is not architecture specific.


The following list describes the Microsoft PE executable format, with the base of the image header at the top. The section from the MS-DOS 2.0 Compatible EXE Header through to the unused section just before the PE header is the MS-DOS 2.0 Section, and is used for MS-DOS compatibility only.


The MS-DOS stub is a valid application that runs under MS-DOS. It is placed at the front of the EXE image. The linker places a default stub here, which prints out the message "This program cannot be run in DOS mode" when the image is run in MS-DOS. The user can specify a different stub by using the /STUB linker option.


At location 0x3c, the stub has the file offset to the PE signature. This information enables Windows to properly execute the image file, even though it has an MS-DOS stub. This file offset is placed at location 0x3c during linking.


After the MS-DOS stub, at the file offset specified at offset 0x3c, is a 4-byte signature that identifies the file as a PE format image file. This signature is "PE\0\0" (the letters "P" and "E" followed by two null bytes).


At the beginning of an object file, or immediately after the signature of an image file, is a standard COFF file header in the following format. Note that the Windows loader limits the number of sections to 96.


Every image file has an optional header that provides information to the loader. This header is optional in the sense that some files (specifically, object files) do not have it. For image files, this header is required. An object file can have an optional header, but generally this header has no function in an object file except to increase its size.


The first field, VirtualAddress, is actually the RVA of the table. The RVA is the address of the table relative to the base address of the image when the table is loaded. The second field gives the size in bytes. The data directories, which form the last part of the optional header, are listed in the following table.


The Certificate Table entry points to a table of attribute certificates. These certificates are not loaded into memory as part of the image. As such, the first field of this entry, which is normally an RVA, is a file pointer instead.


In an image file, the VAs for sections must be assigned by the linker so that they are in ascending order and adjacent, and they must be a multiple of the SectionAlignment value in the optional header.


When determining the image section that will contain the contents of an object section, the linker discards the "$"? and all characters that follow it. Thus, an object section named .text$X actually contributes to the .text section in the image.


However, the characters following the "$"? determine the ordering of the contributions to the image section. All contributions with the same object-section name are allocated contiguously in the image, and the blocks of contributions are sorted in lexical order by object-section name. Therefore, everything in object files with section name .text$X ends up together, after the .text$W contributions and before the .text$Y contributions.


The data structures that were described so far, up to and including the optional header, are all located at a fixed offset from the beginning of the file (or from the PE header if the file is an image that contains an MS-DOS stub).


The remainder of a COFF object or image file contains blocks of data that are not necessarily at any specific file offset. Instead, the locations are defined by pointers in the optional header or a section header.


An exception is for images with a SectionAlignment value of less than the page size of the architecture (4 K for Intel x86 and for MIPS, and 8 K for Itanium). For a description of SectionAlignment, see Optional Header (Image Only). In this case, there are constraints on the file offset of the section data, as described in section 5.1, "Section Data." Another exception is that attribute certificate and debug information must be placed at the very end of an image file, with the attribute certificate table immediately preceding the debug section, because the loader does not map these into memory. The rule about attribute certificate and debug information does not apply to object files, however.


In an image file, the section data must be aligned on a boundary as specified by the FileAlignment field in the optional header. Section data must appear in order of the RVA values for the corresponding sections (as do the individual section headers in the section table).


There are additional restrictions on image files if the SectionAlignment value in the optional header is less than the page size of the architecture. For such files, the location of section data in the file must match its location in memory when the image is loaded, so that the physical offset for section data is the same as the RVA.


Image files do not contain COFF relocations, because all referenced symbols have already been assigned addresses in a flat address space. An image contains relocation information in the form of base relocations in the .reloc section (unless the image has the IMAGE_FILE_RELOCS_STRIPPED attribute). For more information, see The .reloc Section (Image Only).


Attribute certificates can be associated with an image by adding an attribute certificate table. The attribute certificate table is composed of a set of contiguous, quadword-aligned attribute certificate entries. Zero padding is inserted between the original end of the file and the beginning of the attribute certificate table to achieve this alignment. Each attribute certificate entry contains the following fields.


A PE image hash (or file hash) is similar to a file checksum in that the hash algorithm produces a message digest that is related to the integrity of a file. However, a checksum is produced by a simple algorithm and is used primarily to detect whether a block of memory on disk has gone bad and the values stored there have become corrupted. A file hash is similar to a checksum in that it also detects file corruption. However, unlike most checksum algorithms, it is very difficult to modify a file without changing the file hash from its original unmodified value. A file hash can thus be used to detect intentional and even subtle modifications to a file, such as those introduced by viruses, hackers, or Trojan horse programs.


When included in a certificate, the image digest must exclude certain fields in the PE Image, such as the Checksum and Certificate Table entry in Optional Header Data Directories. This is because the act of adding a Certificate changes these fields and would cause a different hash value to be calculated.


The Win32 ImageGetDigestStream function provides a data stream from a target PE file with which to hash functions. This data stream remains consistent when certificates are added to or removed from a PE file. Based on the parameters that are passed to ImageGetDigestStream, other data from the PE image can be omitted from the hash computation. For a link to the function's reference page, see References.


These tables were added to the image to support a uniform mechanism for applications to delay the loading of a DLL until the first call into that DLL. The layout of the tables matches that of the traditional import tables that are described in section 6.4, The .idata Section." Only a few details are discussed here.


As yet, no attribute flags are defined. The linker sets this field to zero in the image. This field can be used to extend the record by indicating the presence of new fields, or it can be used to indicate behaviors to the delay or unload helper functions.


The handle of the DLL to be delay-loaded is in the data section of the image. The phmod field points to the handle. The supplied delay-load helper uses this location to store the handle to the loaded DLL.


The delay import address table (IAT) is referenced by the delay import descriptor through the pIAT field. The delay-load helper updates these pointers with the real entry points so that the thunks are no longer in the calling loop. The function pointers are accessed by using the expression pINT->u1.Function.


However, some COFF sections have special meanings when found in object files or image files. Tools and loaders recognize these sections because they have special flags set in the section header, because special locations in the image optional header point to them, or because the section name itself indicates a special function of the section. (Even if the section name itself does not indicate a special function of the section, the section name is dictated by convention, so the authors of this specification can refer to a section name in all cases.)


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