devices

ICCID activation was once a common workaround for carrier-locked iPhones. Apple patched it, so it cannot issue new unlocked tickets, but tickets created before the patch still work. To preserve an existing unlock through a reset, downgrade, or DFU restore, back up the activation ticket first and restore it afterward. The ticket is tied to one device and cannot be transferred. I use my iPhone 5s (A1453, au/KDDI Japan) as the example.

A memory-modded 360T7 had run for years until I flashed OpenWrt's bl2 and fip. It then stopped at dram size: 0MB. Every rescue package I found failed for the same reason: OpenWrt's official bl2 drives DDR3 at 2133MT/s, while this router has a DDR3-1600 chip. DRAM initialization failed before the rest of the boot chain could load. I traced the settings in the ATF source, built a bl2 at 1866MT/s, and recovered the router over UART.

The Sony DPT-RP1 is a large-screen E Ink reader built for A4 PDFs. Sony ships the same firmware image in China, Japan, and the United States. A region identifier stored outside the firmware selects the UI language, the input methods, and the default font families, so flashing firmware cannot change the region.

The Japanese build has Japanese and English fonts. The American build has English only, while the Chinese build has Chinese and English. My Japanese unit rendered Chinese characters in a book's table of contents with Japanese glyph variants, or did not render them at all. The Chinese and American builds did not have that problem. Their default font families differ.

Making a macOS USB installer becomes awkward when the host and target use different architectures or macOS generations. I ran into it while reinstalling macOS 10.7 Lion on a 2012 Mac Pro from an M1 MacBook Air. The M1 cannot run Lion's installer, and Apple's direct Lion download is packaged in a form that modern macOS refuses to open.