MP 1,1-5,1 Understanding the OpenCore Data variable settings

[startergo]

iMacPro1,1:

OpenCorePkg/AppleModels/DataBase/iMacPro/IMP11.yaml at master · acidanthera/OpenCorePkg

OpenCore bootloader. Contribute to acidanthera/OpenCorePkg development by creating an account on GitHub.

github.com

 

[startergo]

"base64 -D" works. "base64 -d" throws an error

hex=$(echo -n "A1QM4A==" | base64 -d | xxd -u -g 4 -e | sed -E 's/^.+: //;s/ .*//;')
g5@G5s-iMac-Pro ~ % echo 0x$hex
0xE00C5403
g5@G5s-iMac-Pro ~ % echo "obase=2;ibase=16;$hex"|bc
11100000000011000101010000000011

 hex=$(echo -n "A1QM4A==" | base64 -d | xxd -u -g 4 -e | sed -E 's/^.+: //;s/ .*//;') && echo 0x$hex && echo "obase=2;ibase=16;$hex"|bc
0xE00C5403
11100000000011000101010000000011

 

[Dayo]

Must be a bash/zsh thing:

 

[startergo]

Must be a bash/zsh thing:
View attachment 1683390

echo -n "A1QM4A==" | base64 -d | xxd -u -g 4 -e | sed -E 's/^.+: //;s/ .*//;'                
E00C5403

man base64







     --break=count        Insert line breaks every count characters.  Default is 0, which generates an unbroken stream.

     -d
     -D
     --decode             Decode incoming Base64 stream into binary data.

     -h
     --help               Print usage summary and exit.

     -i input_file
     --input=input_file   Read input from input_file.  Default is stdin; passing - also represents stdin.

     -o output_file
     --output=output_file
                          Write output to output_file.  Default is stdout; passing - also represents stdout.

SEE ALSO
     openssl(1), wikipedia page:
           http://en.wikipedia.org/wiki/Base64,
     RFC 4648:
           http://tools.ietf.org/html/rfc4648

Mac OS X 10.7                  February 8, 2011                  Mac OS X 10.7

 

[Dayo]

You are clearly not running bash.
Presume you are on Catalina which uses zsh. Hence the "bash/zsh" mention.

On additional Item posted, not sure what the point being made is but whatever the case, can't argue with error message I got. Now, time to move on?

 

[startergo]

You are clearly not running bash.
Presume you are on Catalina which uses zsh. Hence the "bash/zsh" mention.

On additional Item posted, not sure what the point being made is but whatever the case, can't argue with error message I got. Now, time to move on?

Not sure what is different I tried bash too. I run Big Sur. Anyhow let's move on.

 

[TECK]

hex=$(echo -n "A1QM4A==" | base64 -d | xxd -u -g 4 -e | sed -E 's/^.+: //;s/ .*//;')
g5@G5s-iMac-Pro ~ % echo 0x$hex
0xE00C5403
g5@G5s-iMac-Pro ~ % echo "obase=2;ibase=16;$hex"|bc
11100000000011000101010000000011

 hex=$(echo -n "A1QM4A==" | base64 -d | xxd -u -g 4 -e | sed -E 's/^.+: //;s/ .*//;') && echo 0x$hex && echo "obase=2;ibase=16;$hex"|bc
0xE00C5403
11100000000011000101010000000011

I use Hackintool, might be easier:

I actually made a Python unhexlify method to convert Hex 00 00 00 00 00 00 00 00 00 00 10 00 00 00 00 00 into base64 Data AAAAAAAAAAAAABAAAAAAAA==

 

[startergo]

I use Hackintool, might be easier:

View attachment 1683857

I actually made a Python unhexlify method to convert Hex 00 00 00 00 00 00 00 00 00 00 10 00 00 00 00 00 into base64 Data AAAAAAAAAAAAABAAAAAAAA==

The important thing here is the binary conversion. The Hackintool conversion is certainly not faster then the single-liner above.

 

[TECK]

I think the safest way is always use Hex transformation, regardless the tool. I personally like Hackintool because I just paste the Hex value directly into the Python unhexlify method and I don't have to fiddle with escaped chars or anything else.

I'll give you the perfect example, you need to escape the ASCII string with \0, which is a null terminator used to end the string, for safety reasons. Otherwise your Base64 is wrong, that is why I prefer always Hex values to be passed.

 

[TECK]

echo -n "A1QM4A==" | base64 -d | xxd -u -g 4 -e | sed -E 's/^.+: //;s/ .*//;' E00C5403

That is a Hex (reversed) value, Hex is 03 54 0C E0

 

[startergo]

That is a Hex (reversed) value, Hex is 03 54 0C E0

That is the intention, to convert from Big/Little endian as the values entered in the config file are byte swapped as opposed to the values that you read in the AppleFeatures.h. If you want to analyze the bit changes you have to do the conversion.
BLSupportsLegacyMode.c (apple.com)
CFSwapInt32LittleToHost Converts a 32-bit integer from little-endian format to the host’s native byte order.

 

[Dayo]

not sure how the FirmwareFeaturesMask is calculated. Any idea?

Actually, FirmwareFeaturesMask of 0xFF1FFF3F is the default for cMP5,1 in the OpenCore Apple Database: AppleModels/DataBase/MacPro/MP51.yaml

The actual FirmwareFeatures value in the DB is 0xE80FE137 which is being amended to 0xE00C5403 by the suggestion in the OC Thread. Seems to be removing bits from what's in the cMP5,1 DB but I haven't looked into these bits. Hoping @cdf can shed some light later.