Sabbath School (Суботня Школа)

Offline Bible study app for iPad 1st generation (iOS 5.1.1) — Seventh-day Adventist quarterly lessons with Bible verse popups and translation switcher.

Built with Theos for jailbroken devices.

Features

• 📖 Weekly Sabbath School lessons with full text
• 📜 Bible verse popups with multiple translations (synodal, ERV, UBIO for Ukrainian; NTR, VDC for Romanian)
• 🌙 Dark mode (applies to all screens)
• 🔤 Font size & family picker
• 📝 Notes per day (saved locally)
• ✅ Read progress tracking per lesson
• 👆 Swipe between days, fullscreen reading mode
• 🔄 Auto-opens today's lesson on launch
• 🌐 91 languages via Adventech API (Ukrainian, Romanian, English + all others)
• 🔒 TLS 1.2 via statically linked OpenSSL + libcurl (bypasses iOS 5 TLS 1.0 limitation)
• 💾 Smart caching: shows local data instantly, silently refreshes from API in background

Screenshots

iPad 1G, iOS 5.1.1

Architecture

File	Description
SSAppDelegate.m	App launch, auto-open today's lesson
SSLanguageVC.m	Language selection (uk/ro/en + 91 languages from API)
SSQuarterliesVC.m	List of quarterly studies
SSLessonsVC.m	List of lessons with read progress
SSReadVC.m	Main reader — UIWebView with HTML content, verse popups, notes, font/theme controls
SSAPIClient.m	Data loader: cache (Documents) → bundle → API. Background refresh silently
SSHTTPClient.m	HTTP client using libcurl + OpenSSL for TLS 1.2 on iOS 5
download_days.py	Script to fetch lesson data from API
build_openssl.sh	Cross-compile OpenSSL 1.1.1w for armv7
build_curl.sh	Cross-compile libcurl 7.88.1 with OpenSSL for armv7
lib/libssl.a	OpenSSL SSL static library (armv7)
lib/libcrypto.a	OpenSSL Crypto static library (armv7)
lib/libcurl.a	libcurl static library (armv7, with OpenSSL backend)

Data Source

All lesson data comes from the open Adventech API:

https://sabbath-school.adventech.io/api/v2/{lang}/quarterlies/index.json
https://sabbath-school.adventech.io/api/v2/{lang}/quarterlies/{qid}/lessons/index.json
https://sabbath-school.adventech.io/api/v2/{lang}/quarterlies/{qid}/lessons/{lid}/index.json
https://sabbath-school.adventech.io/api/v2/{lang}/quarterlies/{qid}/lessons/{lid}/days/{did}/read/index.json

Note: All API endpoints require /index.json suffix — without it the server returns HTML (SPA) instead of JSON.

Data is pre-downloaded and bundled in Resources/data/ for offline use. If local data is missing, the app fetches from the API via TLS 1.2 (libcurl + OpenSSL).

Data structure

data/{lang}/quarterlies.json                         — list of quarterlies
data/{lang}/{quarter}/lessons.json                   — lessons in a quarter
data/{lang}/{quarter}/{lesson}/index.json            — lesson detail with days
data/{lang}/{quarter}/{lesson}/{day}.json            — day content with Bible verses

Prerequisites

Tool	Purpose	Location
WSL (Windows Subsystem for Linux)	Build environment	Windows feature
Theos	iOS build system	~/theos in WSL
Clang 11.1 cross-compiler	Compiles for armv7	~/theos/toolchain/linux/iphone/bin/clang
iPhoneOS 9.3 SDK	iOS headers & libs	~/theos/sdks/iPhoneOS9.3.sdk
ldid	Ad-hoc code signing	On iPad via Cydia
Python 3	For downloading lesson data	WSL or Windows
Jailbroken iPad 1G	Target device, SSH enabled	Same Wi-Fi, IP 192.168.1.128

iPad setup (one-time via Cydia)

• OpenSSH (for SSH/SCP access)
• ldid (for code signing)
• Default SSH: root / alpine

Build

Important: NTFS gives 777 permissions which breaks dpkg. Always copy to native Linux filesystem (/tmp/) first.

Important: WSL /tmp/ is volatile — files disappear between sessions. The SSH password helper must be recreated each session.

# Copy to Linux fs, fix permissions, build
wsl bash -lc '
  rm -rf /tmp/ss_build &&
  cp -r /mnt/c/Source/ss_ios /tmp/ss_build &&
  cd /tmp/ss_build &&
  chmod 0755 layout/DEBIAN &&
  ~/theos/toolchain/linux/iphone/bin/ranlib lib/libcrypto.a 2>/dev/null;
  ~/theos/toolchain/linux/iphone/bin/ranlib lib/libssl.a 2>/dev/null;
  ~/theos/toolchain/linux/iphone/bin/ranlib lib/libcurl.a 2>/dev/null;
  export THEOS=~/theos &&
  make clean && make package
'

The .deb package appears in /tmp/ss_build/packages/.

Deploy to iPad

Default iPad SSH: root@192.168.1.128, password: alpine

1. Create SSH password helper (once per WSL session)

Old iPad requires legacy SSH algorithms. This helper avoids interactive password prompts:

wsl bash -lc '
  cat > /tmp/sshpw.sh << "EOF"
#!/bin/bash
echo alpine
EOF
  chmod +x /tmp/sshpw.sh
'

2. Copy, install, sign, respring (one command)

wsl bash -lc '
  DEB=$(ls -t /tmp/ss_build/packages/*.deb | head -1) &&
  cp "$DEB" /tmp/ss.deb &&
  export SSH_ASKPASS=/tmp/sshpw.sh SSH_ASKPASS_REQUIRE=force DISPLAY=:0 &&
  SSH_OPTS="-o StrictHostKeyChecking=no -o HostKeyAlgorithms=+ssh-rsa,ssh-dss -o PubkeyAcceptedAlgorithms=+ssh-rsa" &&
  scp $SSH_OPTS /tmp/ss.deb root@192.168.1.128:/tmp/ss.deb &&
  ssh $SSH_OPTS root@192.168.1.128 "
    killall SabbathSchool 2>/dev/null;
    dpkg -r com.adventist.sabbathschool;
    dpkg -i /tmp/ss.deb;
    ldid -S /Applications/SabbathSchool.app/SabbathSchool;
    killall SpringBoard
  "
'

After SpringBoard respring, the app appears on the home screen.

Update Lesson Data (New Quarter)

1. Edit QID in download_days.py (e.g. 2026-02)
2. Run the download script:

   python3 download_days.py

3. Copy downloaded data into the app bundle:

   cp -r data/* Resources/data/

4. Rebuild and deploy (see above)

Rebuilding TLS Libraries (if needed)

The pre-built lib/libssl.a, lib/libcrypto.a, and lib/libcurl.a are included in the repo. You do NOT need to rebuild them for normal app development. Only rebuild if you need to update OpenSSL/curl versions.

Why custom TLS?

iPad 1G (iOS 5.1.1) only supports TLS 1.0 natively via NSURLConnection/SecureTransport. Modern servers require TLS 1.2+. We statically link OpenSSL + libcurl to bypass the OS limitation.

OpenSSL 1.1.1w

wsl bash -lc "bash /mnt/c/Source/ss_ios/build_openssl.sh"

What it does:

1. Downloads OpenSSL 1.1.1w source to ~/openssl-build/
2. Configures with linux-generic32 target (NOT ios-cross — that one breaks with our clang)
3. Sets CC to Theos clang: -target arm-apple-darwin11 -arch armv7 -isysroot iPhoneOS9.3.sdk
4. Must generate headers first — make include/openssl/opensslconf.h (perl-based, fails silently if skipped)
5. Builds libcrypto.a (~2.7M) and libssl.a (~573K)
6. Copies .a files to lib/ and headers to include/openssl/

Key configure flags: no-shared no-dso no-engine no-tests no-asm no-async -DOPENSSL_NO_SECURE_MEMORY

Known issues:

• ar rcs flag causes ranlib: error: Invalid option: '-f' — use llvm-ar or ar rc + separate ranlib
• Must create cc symlink: ln -sf $TOOLCHAIN/clang $TOOLCHAIN/cc
• Warnings about "no symbols" in some .o files are normal (platform-specific stubs)

libcurl 7.88.1

wsl bash -lc "bash /mnt/c/Source/ss_ios/build_curl.sh"

What it does:

1. Downloads curl 7.88.1 source to ~/curl-build/
2. Creates a manual curl_config.h — autotools ./configure cannot cross-compile (fails at "checking whether we are cross compiling" and can't detect OpenSSL via link test)
3. Compiles all .c files in lib/, lib/vtls/, lib/vauth/ individually with Theos clang
4. Creates libcurl.a (~487K) with llvm-ar (standard ar has ranlib flag issues)
5. Copies .a to lib/ and headers to include/curl/

Key defines in curl_config.h:

• USE_OPENSSL 1 — enables OpenSSL backend
• HAVE_STDBOOL_H 1 — required, without it bool type is undefined and nothing compiles
• CURL_DISABLE_SMB/FTP/FILE/... — disables unused protocols (SMB missing symbol caused crash!)

Disabled protocols: LDAP, DICT, TELNET, TFTP, POP3, IMAP, SMTP, GOPHER, MQTT, RTSP, SMB, FTP, FILE

Skip list (files not compiled): curl_ntlm_core, curl_ntlm_wb, openldap, ldap, telnet, dict, tftp, imap, pop3, smtp, gopher, mqtt, rtsp, pingpong, bufq, bufref

Makefile integration

SabbathSchool_CFLAGS = -fobjc-arc -Wno-deprecated-declarations -Iinclude
SabbathSchool_LDFLAGS = -Wl,-undefined,dynamic_lookup -Wl,-flat_namespace -Llib -lcurl -lssl -lcrypto -lz
SabbathSchool_FRAMEWORKS = UIKit Foundation CoreGraphics Security

Link order matters: -lcurl before -lssl before -lcrypto, then -lz (system zlib).

How TLS is used in the app

1. SSHTTPClient wraps libcurl C API — single static method +[SSHTTPClient fetchURL:]
2. curl_global_init(CURL_GLOBAL_SSL) runs once at class load via +initialize
3. SSL verification is disabled (CURLOPT_SSL_VERIFYPEER = 0) because iOS 5 has no CA bundle accessible to the app
4. SSAPIClient tries local bundle first, falls back to SSHTTPClient in background thread if file not found
5. API URLs require /index.json suffix (e.g. .../quarterlies/index.json)

Troubleshooting

Problem	Solution
No route to host	iPad is sleeping or not on Wi-Fi. Wake it up
Connection refused	OpenSSH not running on iPad. Reboot iPad
Permission denied (SSH)	SSH password helper expired. Recreate /tmp/sshpw.sh (see Deploy)
DEBIAN permissions error	Building on NTFS. Copy to /tmp/ first (see Build)
lib.a: no table of contents*	Run ranlib on .a files before building (see Build)
**Symbol not found: Curl_handler*`	Missing CURL_DISABLE_* in curl_config.h. Add the define and rebuild curl
unknown type name 'bool'	Missing HAVE_STDBOOL_H in curl_config.h
opensslconf.h not found	Run make include/openssl/opensslconf.h in OpenSSL source dir before building
White screen on launch	Data files missing in Resources/data/. Run download_days.py
App crashes on launch	Check crash log: ssh root@iPad "cat /var/mobile/Library/Logs/CrashReporter/LatestCrash-SabbathSchool.plist" — look for "Symbol not found"
ar: Invalid option '-f'	Use llvm-ar instead of ar in build scripts

Tech Stack

• Language: Objective-C (ARC)
• UI: UIKit + UIWebView (HTML/CSS/JS for lesson content)
• Build: Theos, targeting armv7 / iOS 5.0+
• TLS: OpenSSL 1.1.1w + libcurl 7.88.1 (static, for TLS 1.2 on iOS 5)
• Signing: ldid -S (ad-hoc, jailbroken only)
• Package: .deb via dpkg

License

This project uses lesson data from Adventech (open API).