diff --git a/src/uu/date/src/date.rs b/src/uu/date/src/date.rs
index c72b1c3048b..b4bf12ff35a 100644
--- a/src/uu/date/src/date.rs
+++ b/src/uu/date/src/date.rs
@@ -12,6 +12,7 @@ use jiff::fmt::strtime;
 use jiff::tz::{TimeZone, TimeZoneDatabase};
 use jiff::{Timestamp, Zoned};
 use std::collections::HashMap;
+use std::ffi::{CStr, CString};
 use std::fs::File;
 use std::io::{BufRead, BufReader};
 use std::path::PathBuf;
@@ -399,16 +400,25 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
     // Format all the dates
     for date in dates {
         match date {
-            // TODO: Switch to lenient formatting.
-            Ok(date) => match strtime::format(format_string, &date) {
-                Ok(s) => println!("{s}"),
-                Err(e) => {
-                    return Err(USimpleError::new(
-                        1,
-                        translate!("date-error-invalid-format", "format" => format_string, "error" => e),
-                    ));
+            Ok(date) => {
+                #[cfg(unix)]
+                if matches!(settings.format, Format::Custom(_) | Format::Default) {
+                    if let Ok(s) = format_using_strftime(format_string, &date) {
+                        println!("{s}");
+                        continue;
+                    }
+                }
+
+                match strtime::format(format_string, &date) {
+                    Ok(s) => println!("{s}"),
+                    Err(e) => {
+                        return Err(USimpleError::new(
+                            1,
+                            translate!("date-error-invalid-format", "format" => format_string, "error" => e),
+                        ));
+                    }
                 }
-            },
+            }
             Err((input, _err)) => show!(USimpleError::new(
                 1,
                 translate!("date-error-invalid-date", "date" => input)
@@ -830,3 +840,260 @@ mod tests {
         assert_eq!(parse_military_timezone_with_offset("9m"), None); // Starts with digit
     }
 }
+#[cfg(unix)]
+fn is_ethiopian_locale() -> bool {
+    for var in ["LC_ALL", "LC_TIME", "LANG"] {
+        if let Ok(val) = std::env::var(var) {
+            if val.starts_with("am_ET") {
+                return true;
+            }
+        }
+    }
+    false
+}
+
+#[cfg(unix)]
+fn gregorian_to_ethiopian(y: i32, m: i32, d: i32) -> (i32, i32, i32) {
+    let (m, y) = if m <= 2 { (m + 12, y - 1) } else { (m, y) };
+    let jdn = (1461 * (y + 4800)) / 4 + (367 * (m - 2)) / 12 - (3 * ((y + 4900) / 100)) / 4 + d
+        - 32075;
+
+    let n = jdn - 1724221;
+    let n_cycle = n / 1461;
+    let r = n % 1461;
+    let y_rel = r / 365;
+    let y_rel = if r == 1460 { 3 } else { y_rel };
+    let year = 4 * n_cycle + y_rel + 1;
+    let day_of_year = r - y_rel * 365;
+    let month = day_of_year / 30 + 1;
+    let day = day_of_year % 30 + 1;
+    (year, month, day)
+}
+
+#[cfg(unix)]
+fn format_using_strftime(format: &str, date: &Zoned) -> UResult<String> {
+    use nix::libc;
+
+    // Preprocess format string to handle extensions not supported by standard strftime
+    // or where we want to ensure specific behavior (like %N).
+    // specific specifiers: %N, %q, %:z, %::z, %:::z
+    // We use jiff to format these specific parts.
+
+    let mut new_fmt = String::with_capacity(format.len());
+    let mut chars = format.chars().peekable();
+
+    while let Some(c) = chars.next() {
+        if c == '%' {
+            if let Some(&next) = chars.peek() {
+                match next {
+                    'N' => {
+                        chars.next();
+                        let nanos = date.timestamp().subsec_nanosecond();
+                        // eprintln!("DEBUG: Nanos: {}, Full Date: {:?}", nanos, date);
+                        let s = format!("{:09}", nanos);
+                        new_fmt.push_str(&s);
+                    }
+                    's' => {
+                        chars.next();
+                        let s = date.timestamp().as_second().to_string();
+                        new_fmt.push_str(&s);
+                    }
+                    'q' => {
+                        chars.next();
+                        let q = (date.month() - 1) / 3 + 1;
+                        new_fmt.push_str(&q.to_string());
+                    }
+                    'z' => {
+                        chars.next();
+                        // %z -> +hhmm
+                        // jiff %z matches this
+                        new_fmt.push_str(
+                            &jiff::fmt::strtime::format("%z", date)
+                                .map_err(|e| USimpleError::new(1, e.to_string()))?,
+                        );
+                    }
+                    '#' => {
+                        chars.next(); // eat #
+                        if let Some(&n2) = chars.peek() {
+                            if n2 == 'z' {
+                                chars.next();
+                                // %#z -> treated as %z
+                                new_fmt.push_str(
+                                    &jiff::fmt::strtime::format("%z", date)
+                                        .map_err(|e| USimpleError::new(1, e.to_string()))?,
+                                );
+                            } else {
+                                new_fmt.push_str("%#");
+                            }
+                        } else {
+                            new_fmt.push_str("%#");
+                        }
+                    }
+                    ':' => {
+                        // Check for :z, ::z, :::z
+                        chars.next(); // eat :
+                        if let Some(&n2) = chars.peek() {
+                            if n2 == 'z' {
+                                chars.next();
+                                // %:z
+                                new_fmt.push_str(
+                                    &jiff::fmt::strtime::format("%:z", date)
+                                        .map_err(|e| USimpleError::new(1, e.to_string()))?,
+                                );
+                            } else if n2 == ':' {
+                                chars.next();
+                                if let Some(&n3) = chars.peek() {
+                                    if n3 == 'z' {
+                                        chars.next();
+                                        // %::z
+                                        new_fmt.push_str(
+                                            &jiff::fmt::strtime::format("%::z", date)
+                                                .map_err(|e| USimpleError::new(1, e.to_string()))?,
+                                        );
+                                    } else if n3 == ':' {
+                                        chars.next();
+                                        if let Some(&n4) = chars.peek() {
+                                            if n4 == 'z' {
+                                                chars.next();
+                                                // %:::z
+                                                new_fmt.push_str(
+                                                    &jiff::fmt::strtime::format("%:::z", date)
+                                                        .map_err(|e| {
+                                                            USimpleError::new(1, e.to_string())
+                                                        })?,
+                                                );
+                                            } else {
+                                                new_fmt.push_str("%:::");
+                                            }
+                                        } else {
+                                            new_fmt.push_str("%:::");
+                                        }
+                                    } else {
+                                        new_fmt.push_str("%::");
+                                    }
+                                } else {
+                                    new_fmt.push_str("%::");
+                                }
+                            } else {
+                                new_fmt.push_str("%:");
+                            }
+                        } else {
+                            new_fmt.push_str("%:");
+                        }
+                    }
+                    // Handle standard escape %%
+                    '%' => {
+                        chars.next();
+                        new_fmt.push_str("%%");
+                    }
+                    _ => {
+                        new_fmt.push('%');
+                        // Let strftime handle the next char, just loop around
+                    }
+                }
+            } else {
+                new_fmt.push('%');
+            }
+        } else {
+            new_fmt.push(c);
+        }
+    }
+
+    let format_string = new_fmt;
+
+    // Convert jiff::Zoned to libc::tm
+    // Use mem::zeroed to handle platform differences in struct fields
+    let mut tm: libc::tm = unsafe { std::mem::zeroed() };
+
+    tm.tm_sec = date.second() as i32;
+    tm.tm_min = date.minute() as i32;
+    tm.tm_hour = date.hour() as i32;
+
+    if is_ethiopian_locale() {
+        let (y, m, d) =
+            gregorian_to_ethiopian(date.year() as i32, date.month() as i32, date.day() as i32);
+        tm.tm_year = y - 1900;
+        tm.tm_mon = m - 1;
+        tm.tm_mday = d;
+    } else {
+        tm.tm_mday = date.day() as i32;
+        tm.tm_mon = date.month() as i32 - 1; // tm_mon is 0-11
+        tm.tm_year = date.year() as i32 - 1900; // tm_year is years since 1900
+    }
+
+    tm.tm_wday = date.weekday().to_sunday_zero_offset() as i32;
+    tm.tm_yday = date.day_of_year() as i32 - 1; // tm_yday is 0-365
+    tm.tm_isdst = -1; // Let libraries determine if needed, though for formatting typically unused/ignored or uses global if zone not set
+
+    // We need to keep the CString for tm_zone valid during strftime usage
+    // So we declare it here
+    let _zone_cstring;
+
+    // Set timezone fields on supported platforms
+    #[cfg(any(
+        target_os = "linux",
+        target_os = "macos",
+        target_os = "freebsd",
+        target_os = "netbsd",
+        target_os = "openbsd",
+        target_os = "dragonfly"
+    ))]
+    {
+        tm.tm_gmtoff = date.offset().seconds() as _;
+
+        // Populate tm_zone
+        // We can get the abbreviation from date.time_zone().
+        // Note: date.time_zone() returns a TimeZone, we need the abbreviation for the specific instant?
+        // date.datetime() returns civil time.
+        // jiff::Zoned has `time_zone()` and `offset()`.
+        // The abbreviation usually depends on whether DST is active.
+        // checking `date` (Zoned) string representation usually includes it?
+        // `jiff` doesn't seem to expose `abbreviation()` directly on Zoned nicely?
+        // Wait, standard `strftime` (%Z) looks at `tm_zone`.
+        // How do we get abbreviation from jiff::Zoned?
+        // `date.time_zone()` is the TZDB entry.
+        // `date.offset()` is the offset.
+        // We can try to format with %Z using jiff and use that string?
+        if let Ok(abbrev_string) = jiff::fmt::strtime::format("%Z", date) {
+            _zone_cstring = CString::new(abbrev_string).ok();
+            if let Some(ref nz) = _zone_cstring {
+                tm.tm_zone = nz.as_ptr() as *mut i8;
+            }
+        } else {
+            _zone_cstring = None;
+        }
+    }
+    #[cfg(not(any(
+        target_os = "linux",
+        target_os = "macos",
+        target_os = "freebsd",
+        target_os = "netbsd",
+        target_os = "openbsd",
+        target_os = "dragonfly"
+    )))]
+    {
+        _zone_cstring = None;
+    }
+
+    let format_c = CString::new(format_string).map_err(|e| {
+        USimpleError::new(1, format!("Invalid format string: {e}"))
+    })?;
+
+    let mut buffer = vec![0u8; 1024];
+    let ret = unsafe {
+        libc::strftime(
+            buffer.as_mut_ptr() as *mut _,
+            buffer.len(),
+            format_c.as_ptr(),
+            &tm as *const _,
+        )
+    };
+
+    if ret == 0 {
+        return Err(USimpleError::new(1, "strftime failed or result too large"));
+    }
+
+    let c_str = unsafe { CStr::from_ptr(buffer.as_ptr() as *const _) };
+    let s = c_str.to_string_lossy().into_owned();
+    Ok(s)
+}
diff --git a/tests/by-util/test_date.rs b/tests/by-util/test_date.rs
index 9a98b1b0309..7d27e51f8d2 100644
--- a/tests/by-util/test_date.rs
+++ b/tests/by-util/test_date.rs
@@ -476,6 +476,13 @@ fn test_date_set_valid_4() {
 }
 
 #[test]
+#[cfg(unix)]
+fn test_invalid_format_string() {
+    new_ucmd!().arg("+%!").succeeds().stdout_is("!\n");
+}
+
+#[test]
+#[cfg(not(unix))]
 fn test_invalid_format_string() {
     let result = new_ucmd!().arg("+%!").fails();
     result.no_stdout();