Saturday, 16 September 2017

E2B v1.96a Beta available

Just a couple of small changes (no bugfixes):

v1.96a

  • QRUN.g4b now checks for dynamic/differencing VHDs - only fixed VHDs will boot.
  • Improved GIFtoIMA.cmd script to calculate size of the .IMA file required.
VHDs can be Fixed, Dynamic or Differencing type. E2B can only directly boot the Fixed type of VHD or VHDX file. You can tell by the size which type it is - a 15GB Fixed VHD file will be 15GB in size, the other two types of VHD will usually be a lot less than the 'mounted' size. VHDs created by WinToUSB will work. VHDs created by DiskToVHD will not boot from E2B as they will be Dynamic VHDs.

I have improved the GIFtoIMA.cmd script so that it calculates the required size in KB of the .IMA file needed for animations on the E2B menu. Now you can just press ENTER to accept the suggested size.

Download v1.96a from Alternate Download Areas as usual.


Beware! -  here lies ye Kingdom of Geekland...

Examining file contents using grub4dos

The grub4dos cat command can be used to display the bytes in a file, e.g.

cat --hex --length=32 /fred.bin

However, grub4dos will 'interpret' a file if it recognises it's internal format. For instance,

cat --hex --length=32 /background.bmp.gz

BMP file compressed with gzip
will display the first 32 decompressed bytes and not the actual (compressed) bytes. Similarly,

cat --hex --length=512 /Dynamic.VHD

will display LBA0 (the first disk sector) and not the actual bytes of the Dynamic VHD file which will have a header block starting with the string 'conectix'.

To view the raw bytes (the same bytes you would see if using a hex editor to examine the bytes in a file), we must use:

raw cat --hex --length=512 /Dynamic.VHD

A Dynamic VHD
The same 'translation\decompression' is done for grub4dos when using other commands such as dd and you can also precede those commands with 'raw' to ensure that you get a true (unchanged) copy.

Tip: Using cat --locate=xxx --replace=yyy  you can replace bytes in any file (and even modify an ISO). For instance, I use it to delete the bootfix.bin directory entry from Windows ISOs so that they don't prompt you to 'Press a key to boot from CD' when the ISO is booted by E2B! This code permanently modifies the ISO file after it has been mapped to device (0xff) by grub4dos...

QRUN.g4b
cat --locatei=BOOTFIX.BIN --number=1 --replace=XXX (0xff)+0x3000 > nul && pause --wait=3 WARNING: BOOTFIX.BIN 'Press a key to boot from CD' has now been removed from the ISO file!