diff --git a/core/src/nix/daemon.sld b/core/src/nix/daemon.sld
index 1273334..4bd7406 100644
--- a/core/src/nix/daemon.sld
+++ b/core/src/nix/daemon.sld
@@ -193,7 +193,7 @@
        (set-daemon-link-protocol-minor! link protocol-minor)
        (unless (= worker-magic #x6478696f) (error "handshake: received wrong WORKER_MAGIC_2" worker-magic))
        (unless (= protocol-major 1) (error "handshake: invalid major version protocol" protocol-major))
-       (daemon-write-u64 link #x121)
+       (daemon-write-u64 link #x123)
        (daemon-write-u64 link 0) ; cpu affinity
        (daemon-write-u64 link 0)
        (daemon-flush link)
@@ -202,6 +202,7 @@
          (set! daemon-version (daemon-read-string link)))
        (when (< protocol-minor #x20)
          (error (string-append "Nix daemon version " daemon-version " is too old!")))
+       (daemon-read-u64 link) ; trusted
        (set-daemon-link-daemon-version! link daemon-version)
        (daemon-read-log-events link)
        (daemon-wop-set-options link))
@@ -262,17 +263,40 @@
             (daemon-read-log-events link)
             (daemon-read-u64 link)))
 
+   ;; Process a framed sink.
+   ;; `proc` will be called to provide the contents.
+   (define (handle-framed-sink link proc)
+     (define write-blob
+       (case-lambda
+         ((bv) (daemon-write-u64 link (bytevector-length bv)) (write-bytevector bv (daemon-link-out-port link)))
+         ((bv start) (daemon-write-u64 link (- (bytevector-length bv) start)) (write-bytevector bv (daemon-link-out-port link) start))
+         ((bv start end) (daemon-write-u64 link (- end start)) (write-bytevector bv (daemon-link-out-port link) start end))))
+
+     (define data-thread
+       (make-thread
+         (lambda ()
+           (proc write-blob)
+           (daemon-write-u64 link 0) ; send an EOF
+           (daemon-flush link))))
+     (thread-start! data-thread)
+     (daemon-read-log-events link)
+     (thread-join! data-thread))
+
    ;; Write a simple text file to the store. `refs` is expected to be sorted.
    ;; Returns the (string) store path at which the file has been created.
+   ;; Actually calls `AddToStore` internally.
    (define (daemon-wop-add-text-to-store link suffix s refs)
-       (daemon-write-u64 link 8)
+       (daemon-write-u64 link 7)
        (daemon-write-string link suffix)
-       (daemon-write-string link s)
+       (daemon-write-string link "text:sha256")
        (daemon-write-u64 link (length refs))
        (for-each (lambda (l) (daemon-write-string link l)) refs)
+       (daemon-write-u64 link 0) ; repair flag
        (daemon-flush link)
-       (daemon-read-log-events link)
-       (daemon-read-string link))
+       (handle-framed-sink link (lambda (write-blob) (write-blob (string->utf8 s))))
+       (define path (daemon-read-string link))
+       (daemon-read-valid-path-info link)
+       path)
 
    ;; Contains the information Nix stores about a valid store path.
    (define-record-type <valid-path-info>
@@ -355,21 +379,7 @@
      (daemon-write-u64 link 0) ; dontCheckSigs
 
      (daemon-flush link)
-     (define write-blob
-       (case-lambda
-         ((bv) (daemon-write-u64 link (bytevector-length bv)) (write-bytevector bv (daemon-link-out-port link)))
-         ((bv start) (daemon-write-u64 link (- (bytevector-length bv) start)) (write-bytevector bv (daemon-link-out-port link) start))
-         ((bv start end) (daemon-write-u64 link (- end start)) (write-bytevector bv (daemon-link-out-port link) start end))))
-
-     (define data-thread
-       (make-thread
-         (lambda ()
-           (proc write-blob)
-           (daemon-write-u64 link 0) ; send an EOF
-           (daemon-flush link))))
-     (thread-start! data-thread)
-     (daemon-read-log-events link)
-     (thread-join! data-thread))
+     (handle-framed-sink link proc))
 
    ;; Requests an alist of output name to output store path for the derivation at `store-path`.
    (define (daemon-wop-query-derivation-output-map link store-path)