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@Cryptiiiic
Cryptiiiic / ios16_downgrading.txt
Created March 1, 2023 00:10
The unfortunate state of iOS downgrading
Unfortunately I have some bad news for downgrading.
Before I explain the bad news at the end of this post, I first need to introduce a background of iOS devices.
In iOS 16, Apple introduced a new firmware component known as Cryptex1. Technically, this is a "virtual" co-processor.
It's purpose is to allow Apple to push RSRs (Rapid Security Responses) which are separate from traditional iOS updates and can be installed much faster.
Like other firmwares, it also has a signing ticket locked to a cryptographic nonce (number-used-once).
We commonly refer to the Apple signing tickets as SHSH blobs.
Meaning the firmware can't be installed without a valid signing ticket as well as a matching nonce.
The "big two" components we deal with signing/nonces are AP and SEP. AP is basically the main device chip (Application Processor).
SEP is the security chip (Secure Enclave Processor).
With regards to APNonce, Apple conveniently gave us the com.apple.System.boot-nonce NVRAM property which we use to set the APNonce generator.
@tannerdsilva
tannerdsilva / hostXMRNode.md
Last active January 26, 2026 13:34
How To Build And Host a Monero Node from Source

How to Build and Install a Monero Node on a Debian-based System

Hello. In this document, we will walk through the steps of building and hosting your own Monero node from source on a Debian-based Linux system. These systems include Raspbian, Debian (9 and above), and Ubuntu (18.04 and above). This tutorial assumes that you are capable of accessing the ROOT terminal of your Debian-based system, and are capable of getting your system online if necessary. You may plan on using an external storage device to store the blockchain, this tutorial will include the optional steps to support external storage. Alternatively, this setup procedure can also accomodate users looking to host a pruned blockchain with restricted storage space.

Here are some useful links for reaching this prerequisite if you do not currently have access to a Debian-based system that meets the recommended system requirements.

@howyay
howyay / Setting up Postfix on Debian.md
Last active March 3, 2026 16:16
A guide to set up a Postfix + Dovecot IMAP server with complete spf, dkim and dmarc support.

An ultimate guide to Postfix + Dovecot IMAP server with complete SPF, DKIM and DMARC support and additional instructions for a multi-domain setup

In this guide, domain.com will be your root domain and mail.domain.com will be the hostname of your mail server

@earthgecko
earthgecko / bash.generate.random.alphanumeric.string.sh
Last active February 11, 2026 10:15
shell/bash generate random alphanumeric string
#!/bin/bash
# bash generate random alphanumeric string
#
# bash generate random 32 character alphanumeric string (upper and lowercase) and
NEW_UUID=$(cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w 32 | head -n 1)
# bash generate random 32 character alphanumeric string (lowercase only)
cat /dev/urandom | tr -dc 'a-z0-9' | fold -w 32 | head -n 1