diff --git a/NAMESPACE b/NAMESPACE
index 06bd81d78..639ef73f2 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -8,6 +8,7 @@ S3method("$",rxSymInvCholEnv)
 S3method("$",rxUi)
 S3method("$<-",rxSolve)
 S3method("$<-",rxSymInvCholEnv)
+S3method("$<-",rxUi)
 S3method("+",rxSolve)
 S3method("+",solveRxDll)
 S3method("[",rxSolve)
@@ -139,6 +140,7 @@ S3method(rxUiGet,lhsTheta)
 S3method(rxUiGet,lhsVar)
 S3method(rxUiGet,lstChr)
 S3method(rxUiGet,md5)
+S3method(rxUiGet,model)
 S3method(rxUiGet,modelDesc)
 S3method(rxUiGet,modelFun)
 S3method(rxUiGet,muRefTable)
diff --git a/R/rxUiGet.R b/R/rxUiGet.R
index 7ab14730c..af43f75cd 100644
--- a/R/rxUiGet.R
+++ b/R/rxUiGet.R
@@ -235,6 +235,7 @@ rxUiGet.iniFun <- function(x, ...) {
 }
 attr(rxUiGet.iniFun, "desc") <- "normalized, quoted `ini()` block"
 
+
 #' @export
 #' @rdname rxUiGet
 rxUiGet.modelFun <- function(x, ...) {
@@ -243,6 +244,11 @@ rxUiGet.modelFun <- function(x, ...) {
 }
 attr(rxUiGet.modelFun, "desc") <- "normalized, quoted `model()` block"
 
+#' @export
+#' @rdname rxUiGet
+rxUiGet.model <- rxUiGet.modelFun
+
+
 #' @export
 #' @rdname rxUiGet
 rxUiGet.modelDesc <- function(x, ...) {
@@ -365,8 +371,15 @@ attr(rxUiGet.covLhs, "desc") <- "cov->lhs translation"
 #' @rdname rxUiGet
 rxUiGet.default <- function(x, ...) {
   .arg <- class(x)[1]
-  if (!exists(.arg, envir=x[[1]])) return(NULL)
-  get(.arg, x[[1]])
+  .ui <- x[[1]]
+  if (!exists(.arg, envir=.ui)) {
+    .meta <- get("meta", envir=.ui)
+    if (exists(.arg, envir=.meta)) {
+      return(get(.arg, envir=.meta))
+    }
+    return(NULL)
+  }
+  get(.arg, .ui)
 }
 
 .rxUiGetEnvInfo <- c("model"="Original Model (with comments if available)",
diff --git a/R/ui-assign-parts.R b/R/ui-assign-parts.R
index 19e4863b3..057a860eb 100644
--- a/R/ui-assign-parts.R
+++ b/R/ui-assign-parts.R
@@ -291,3 +291,30 @@
 `RxODE<-` <- function(x, envir=environment(x), value) {
   UseMethod("rxode2<-")
 }
+
+#' @export
+`$<-.rxUi` <- function(x, name, value) {
+  .raw <- inherits(x, "raw")
+  if (!.raw) {
+    assign(name, value, envir=x)
+    return(x)
+  }
+  .x <- x
+  if (name %in% c("ini", "iniDf")) {
+    ini(x) <- value
+    return(x)
+  }
+  if (name == "model") {
+    model(x) <- value
+    return(x)
+  }
+  .x <- rxUiDecompress(.x)
+  if (exists(name, .x)) {
+    stop("'", name, "' is a fixed UI component and should not be overwritten",
+         call.=FALSE)
+  }
+  .meta <- get("meta", .x)
+  assign(name, value, envir=.meta)
+  .x <- rxUiCompress(.x)
+  .x
+}
diff --git a/man/reexports.Rd b/man/reexports.Rd
index f1310e9e9..365c14ab7 100644
--- a/man/reexports.Rd
+++ b/man/reexports.Rd
@@ -82,3 +82,4 @@ below to see their documentation.
   \item{rxode2random}{\code{\link[rxode2random:dot-cbindOme]{.cbindOme}}, \code{\link[rxode2random:dot-expandPars]{.expandPars}}, \code{\link[rxode2random:dot-vecDf]{.vecDf}}, \code{\link[rxode2random]{cvPost}}, \code{\link[rxode2random]{invWR1d}}, \code{\link[rxode2random]{phi}}, \code{\link[rxode2random]{rinvchisq}}, \code{\link[rxode2random]{rLKJ1}}, \code{\link[rxode2random]{rxGetSeed}}, \code{\link[rxode2random]{rxGetSeed}}, \code{\link[rxode2random]{rxRmvn}}, \code{\link[rxode2random]{rxSeedEng}}, \code{\link[rxode2random]{rxSetSeed}}, \code{\link[rxode2random]{rxSetSeed}}, \code{\link[rxode2random]{rxSetSeed}}, \code{\link[rxode2random:rxWithSeed]{rxWithPreserveSeed}}, \code{\link[rxode2random]{rxWithSeed}}, \code{\link[rxode2random]{rxWithSeed}}}
 }}
 
+\value{ Inherited from parent routine }
diff --git a/man/rxUiGet.Rd b/man/rxUiGet.Rd
index 0b012c9d2..0f297005c 100644
--- a/man/rxUiGet.Rd
+++ b/man/rxUiGet.Rd
@@ -23,6 +23,7 @@
 \alias{rxUiGet.ini}
 \alias{rxUiGet.iniFun}
 \alias{rxUiGet.modelFun}
+\alias{rxUiGet.model}
 \alias{rxUiGet.modelDesc}
 \alias{rxUiGet.thetaLower}
 \alias{rxUiGet.thetaUpper}
@@ -81,6 +82,8 @@ rxUiGet(x, ...)
 
 \method{rxUiGet}{modelFun}(x, ...)
 
+\method{rxUiGet}{model}(x, ...)
+
 \method{rxUiGet}{modelDesc}(x, ...)
 
 \method{rxUiGet}{thetaLower}(x, ...)
diff --git a/man/rxode2.Rd b/man/rxode2.Rd
index dc6d9aeb7..215a15ee6 100644
--- a/man/rxode2.Rd
+++ b/man/rxode2.Rd
@@ -333,7 +333,7 @@ compilation model.
 
 \if{html}{\out{<div class="sourceCode">}}\preformatted{## using C compiler: ‘gcc (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0’
 
-## rxode2 2.0.14.9000 model named rx_4d7e23c27b311c0b8fa7436caae3124f model (ready). 
+## rxode2 2.0.14.9000 model named rx_f8a38012c74774242195a2bca079f175 model (ready). 
 ## x$state: depot, center
 ## x$stateExtra: cp
 ## x$params: tka, tcl, tv, add.sd, eta.ka, eta.cl, eta.v, rxerr.cp
@@ -346,7 +346,7 @@ mod$simulationIniModel
 
 \if{html}{\out{<div class="sourceCode">}}\preformatted{## using C compiler: ‘gcc (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0’
 
-## rxode2 2.0.14.9000 model named rx_175d15ed553ae1eccaf047d565b24f55 model (ready). 
+## rxode2 2.0.14.9000 model named rx_8367e8f5e6c5a00454c7193fc896bf87 model (ready). 
 ## x$state: depot, center
 ## x$stateExtra: cp
 ## x$params: tka, tcl, tv, add.sd, eta.ka, eta.cl, eta.v, rxerr.cp
diff --git a/src/RcppExports.cpp b/src/RcppExports.cpp
index 0432f25fd..796b4ba1d 100644
--- a/src/RcppExports.cpp
+++ b/src/RcppExports.cpp
@@ -67,7 +67,7 @@ RcppExport SEXP _rxode2_rxExpandGrid_(SEXP c1SEXP, SEXP c2SEXP, SEXP typeSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -102,7 +102,7 @@ RcppExport SEXP _rxode2_rxExpandSens_(SEXP stateSEXP, SEXP calcSensSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -138,7 +138,7 @@ RcppExport SEXP _rxode2_rxExpandSens2_(SEXP stateSEXP, SEXP s1SEXP, SEXP s2SEXP)
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -175,7 +175,7 @@ RcppExport SEXP _rxode2_rxExpandFEta_(SEXP stateSEXP, SEXP netaSEXP, SEXP predSE
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -209,7 +209,7 @@ RcppExport SEXP _rxode2_rxRepR0_(SEXP netaSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -245,7 +245,7 @@ RcppExport SEXP _rxode2_rxExpandNesting(SEXP objSEXP, SEXP nestingInfoSEXP, SEXP
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -291,7 +291,7 @@ RcppExport SEXP _rxode2_rxIs(SEXP objSEXP, SEXP clsSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -325,7 +325,7 @@ RcppExport SEXP _rxode2_getRxFn(SEXP nameSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -359,7 +359,7 @@ RcppExport SEXP _rxode2_dynLoad(SEXP dllSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -393,7 +393,7 @@ RcppExport SEXP _rxode2_rxModelVars_(SEXP objSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -428,7 +428,7 @@ RcppExport SEXP _rxode2_rxState(SEXP objSEXP, SEXP stateSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -462,7 +462,7 @@ RcppExport SEXP _rxode2_rxParams_(SEXP objSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -496,7 +496,7 @@ RcppExport SEXP _rxode2_rxDfdy(SEXP objSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -530,7 +530,7 @@ RcppExport SEXP _rxode2_rxLhs(SEXP objSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -570,7 +570,7 @@ RcppExport SEXP _rxode2_rxInits(SEXP objSEXP, SEXP vecSEXP, SEXP reqSEXP, SEXP d
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -605,7 +605,7 @@ RcppExport SEXP _rxode2_rxSetupIni(SEXP objSEXP, SEXP initsSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -641,7 +641,7 @@ RcppExport SEXP _rxode2_rxSetupScale(SEXP objSEXP, SEXP scaleSEXP, SEXP extraArg
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -674,7 +674,7 @@ RcppExport SEXP _rxode2_atolRtolFactor_(SEXP factorSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -735,7 +735,7 @@ RcppExport SEXP _rxode2_rxSimThetaOmega(SEXP paramsSEXP, SEXP omegaSEXP, SEXP om
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -768,7 +768,7 @@ RcppExport SEXP _rxode2_rxSolveFree() {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -809,7 +809,7 @@ RcppExport SEXP _rxode2_rxSolve_(SEXP objSEXP, SEXP rxControlSEXP, SEXP specPara
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -843,7 +843,7 @@ RcppExport SEXP _rxode2_rxSolveDollarNames(SEXP objSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -879,7 +879,7 @@ RcppExport SEXP _rxode2_rxSolveGet(SEXP objSEXP, SEXP argSEXP, SEXP exactSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -915,7 +915,7 @@ RcppExport SEXP _rxode2_rxSolveUpdate(SEXP objSEXP, SEXP argSEXP, SEXP valueSEXP
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -956,7 +956,7 @@ RcppExport SEXP _rxode2_rxSolveSEXP(SEXP objSSEXP, SEXP rxControlSSEXP, SEXP spe
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -989,7 +989,7 @@ RcppExport SEXP _rxode2_rxRmModelLib_(SEXP strSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1023,7 +1023,7 @@ RcppExport SEXP _rxode2_rxGetrxode2(SEXP objSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1057,7 +1057,7 @@ RcppExport SEXP _rxode2_rxIsCurrent(SEXP objSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1090,7 +1090,7 @@ RcppExport SEXP _rxode2_rxAssignPtr(SEXP objectSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1124,7 +1124,7 @@ RcppExport SEXP _rxode2_rxDll(SEXP objSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1158,7 +1158,7 @@ RcppExport SEXP _rxode2_rxC(SEXP objSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1192,7 +1192,7 @@ RcppExport SEXP _rxode2_rxIsLoaded(SEXP objSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1226,7 +1226,7 @@ RcppExport SEXP _rxode2_rxDynLoad(SEXP objSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1260,7 +1260,7 @@ RcppExport SEXP _rxode2_rxLock(SEXP objSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1294,7 +1294,7 @@ RcppExport SEXP _rxode2_rxUnlock(SEXP objSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1328,7 +1328,7 @@ RcppExport SEXP _rxode2_rxAllowUnload(SEXP allowSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1361,7 +1361,7 @@ RcppExport SEXP _rxode2_rxUnloadAll_() {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1395,7 +1395,7 @@ RcppExport SEXP _rxode2_rxDynUnload(SEXP objSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1429,7 +1429,7 @@ RcppExport SEXP _rxode2_rxDelete(SEXP objSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1463,7 +1463,7 @@ RcppExport SEXP _rxode2_setRstudio(SEXP isRstudioSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1497,7 +1497,7 @@ RcppExport SEXP _rxode2_setProgSupported(SEXP isSupportedSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1530,7 +1530,7 @@ RcppExport SEXP _rxode2_getProgSupported() {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1566,7 +1566,7 @@ RcppExport SEXP _rxode2_rxUpdateTrans_(SEXP retSEXP, SEXP prefixSEXP, SEXP libNa
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1600,7 +1600,7 @@ RcppExport SEXP _rxode2_dropUnitsRxSolve(SEXP xSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1634,7 +1634,7 @@ RcppExport SEXP _rxode2_rxSetSilentErr(SEXP silentSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1668,7 +1668,7 @@ RcppExport SEXP _rxode2_rxInv(SEXP matrixSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1705,7 +1705,7 @@ RcppExport SEXP _rxode2_rxSymInvChol(SEXP invObjOrMatrixSEXP, SEXP thetaSEXP, SE
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1741,7 +1741,7 @@ RcppExport SEXP _rxode2_rxSymInvCholEnvCalculate(SEXP objSEXP, SEXP whatSEXP, SE
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1786,7 +1786,7 @@ RcppExport SEXP _rxode2_isNullZero(SEXP objSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1820,7 +1820,7 @@ RcppExport SEXP _rxode2_rxErf(SEXP vSEXP) {
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1859,7 +1859,7 @@ RcppExport SEXP _rxode2_binomProbsPredVec_(SEXP nSEXP, SEXP mSEXP, SEXP YSEXP, S
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1897,7 +1897,7 @@ RcppExport SEXP _rxode2_binomProbs_(SEXP xSEXP, SEXP probsSEXP, SEXP naRmSEXP, S
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
@@ -1936,7 +1936,7 @@ RcppExport SEXP _rxode2_meanProbs_(SEXP xSEXP, SEXP probsSEXP, SEXP naRmSEXP, SE
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error(CHAR(rcpp_msgSEXP_gen));
+        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;
diff --git a/tests/testthat/test-ui-assign-model-parts.R b/tests/testthat/test-ui-assign-model-parts.R
index 893118824..c90ee6dcb 100644
--- a/tests/testthat/test-ui-assign-model-parts.R
+++ b/tests/testthat/test-ui-assign-model-parts.R
@@ -94,6 +94,12 @@ test_that("rxode2<- and other rxUi methods", {
   expect_equal(body(uiOne$fun), body(rxode2(one.compartment)$fun))
   expect_equal(body(uiTwo$fun), body(rxode2(two.compartment)$fun))
 
+  uiOne <- rxode2(one.compartment)
+  uiOne$model <- model(one.compartment2)
+  expect_equal(model(uiOne), model(one.compartment2))
+  expect_equal(ini(uiOne), ini(one.compartment))
+
+
   uiOne <- rxode2(one.compartment)
 
   model(uiOne) <-  model(one.compartment2)
@@ -143,7 +149,7 @@ test_that("rxode2<- and other rxUi methods", {
   }))
 
   ini(uiOne) <-  iniNew
-  
+
   expect_equal(ini(uiOne), iniNew)
   expect_equal(uiOne$matt, "f")
   expect_equal(uiOne$f, "matt")
@@ -208,7 +214,7 @@ test_that("rxode2<- and other rxUi methods", {
   expect_equal(uiOne$matt, "f")
   expect_equal(uiOne$f, "matt")
   expect_true(inherits(uiOne, "uiOne"))
-    
+
   uiTwo <- uiOne %>%
     model(ka <- tka * exp(eta.ka))
 
@@ -223,7 +229,7 @@ test_that("rxode2<- and other rxUi methods", {
   expect_equal(uiTwo$matt, "f")
   expect_equal(uiTwo$f, "matt")
   expect_true(inherits(uiTwo, "uiOne"))
-    
+
 
   # rename something in the ini block is also an insignificant change
   uiTwo <- uiOne %>%
@@ -257,10 +263,45 @@ test_that("ini(model) <- NULL drops", {
     })
   }
 
-
   uiOne <- one.compartment()
   ini(uiOne) <- NULL
   expect_length(uiOne$iniDf$ntheta, 0L)
   expect_equal(as.ini(NULL), quote(ini({}))) #nolint
+
+  # try with $ini assignment
+  uiOne <- one.compartment()
+  uiOne$ini <- NULL
+  expect_length(uiOne$iniDf$ntheta, 0L)
+  expect_equal(as.ini(NULL), quote(ini({}))) #nolint
 })
 
+test_that("assign model changes meta information", {
+
+  one.compartment <- function() {
+    ini({
+      tka <- log(1.57)
+      tcl <- log(2.72)
+      tv <- log(31.5)
+      eta.ka ~ 0.6
+      eta.cl ~ 0.3
+      eta.v ~ 0.1
+    })
+    model({
+      ka <- exp(tka + eta.ka)
+      cl <- exp(tcl + eta.cl)
+      v <- exp(tv + eta.v)
+      d/dt(depot) = -ka * depot
+      d/dt(center) = ka * depot - cl / v * center
+      cp = center / v
+    })
+  }
+
+  uiOne <- one.compartment()
+
+  uiOne$matt <- "matt"
+
+  expect_equal(uiOne$meta$matt, "matt")
+
+  expect_equal(uiOne$matt, "matt")
+
+})